Source: WASHINGTON STATE UNIVERSITY submitted to NRP
REDUCING THE IMPACT OF INDUSTRY-CRITICAL INSECT AND DISEASE PROBLEMS IN HOPS THROUGH DEVELOPMMENT OF PREVENTATIVE AND PREDICTIVE STRATEGIES
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
COMPLETE
Funding Source
OTHER GRANTS
Reporting Frequency
Annual
Accession No.
1004215
Grant No.
2014-51181-22381
Cumulative Award Amt.
$3,169,180.00
Proposal No.
2014-07882
Multistate No.
(N/A)
Project Start Date
Sep 1, 2014
Project End Date
Aug 31, 2019
Grant Year
2014
Program Code
[SCRI]- Specialty Crop Research Initiative
Recipient Organization
WASHINGTON STATE UNIVERSITY
240 FRENCH ADMINISTRATION BLDG
PULLMAN,WA 99164-0001
Performing Department
Agricultural Research Center
Non Technical Summary
Our project is entitled Reducing the Impact of Industry-Critical Insect and Disease Problems in Hop through Development of Preventive and Predictive Strategies. Over the four-year course of research and extension, we propose to develop and deliver tools to hop growers to help them make better-informed decisions about pest management. We have six stated objectives, each of which is based upon hop industry stakeholder input. The first three objectives are research-based, while the other three support and strengthen the practical application of the research we intend to conduct. Our research objectives all involve developing ways to prevent or predict negative impacts of pests (i.e., diseases, arthropods, and weeds) on hop. Objective 1 is assessing how water and nutrient levels impact hop pests. Objective 2 involves identifying risk factors for pest outbreaks, then determining the best timing and methods for managing mites, aphids, and powdery mildew. This multi-part objective includes developing ways to assess the level of resistance (i.e., reduced pesticide susceptibility) in the pest mite populations and looking at powdery mildew control on an area-wide scale. In Objective 3 we take the first steps toward breeding hop plants with improved pest and disease management characteristics while maintaining high flavor quality. Objective 4 is the outreach education we intend to provide to hop growers and other industry stakeholders. In Objective 5 we assess the outcomes of our project outcomes. Objective 6 details our involvement of undergraduate and graduate students in key research and extension roles throughout project.Our team includes entomology, plant pathology, weed science, irrigation engineering, food science, economics, sociology, and communications professionals. Our Advisory Panel includes members of the Hop Industry Plant Protection Committee, representatives of third-party certification programs, and stakeholders in the craft brewing industry. Our multi-state (Washington, Oregon, Idaho, New York) team addresses the full range of climatic conditions and pest complexes to which hops are subjected and over 99% of U.S. hop acreage.This project is a Standard Research and Extension Project (SREP) that addresses SCRI focus areas 1d (plant breeding to improve pest/disease management including resistance) and 2 (identify and address threats from pests and diseases).
Animal Health Component
50%
Research Effort Categories
Basic
50%
Applied
50%
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
2112230101034%
1022230104033%
2122230116033%
Knowledge Area
212 - Pathogens and Nematodes Affecting Plants; 102 - Soil, Plant, Water, Nutrient Relationships; 211 - Insects, Mites, and Other Arthropods Affecting Plants;

Subject Of Investigation
2230 - Hops;

Field Of Science
1040 - Molecular biology; 1160 - Pathology; 1010 - Nutrition and metabolism;
Goals / Objectives
· Objective 1: Discern water/nutrient level impacts on pest complex.· Objective 2: Identify and quantify risk factors that underlie outbreaks of arthropod pests and diseases at multiple spatial scales.o Objective 2a: Develop a damage function and dynamic action threshold for spider mites and hop aphids based on key risk factors.o Objective 2b: Expand robust molecular diagnostics to predict acaricide resistance in the field.o Objective 2c: Develop a predictive model and area-wide management program for powdery mildew in hop.· Objective 3: Characterize and select varieties with disease and arthropod pest resistance traits as a preventive pest management tool.· Objective 4: Conduct timely, targeted education outreach.· Objective 5: Assess outcomes from a physical science, economic, and sociological standpoint, as well as assessing changes in knowledge and production practices.· Objective 6: Mentor the next generation of scientists by involving undergraduate and graduate students in key research and extension activities.
Project Methods
Objective 1: Water/Nutrient Level Impacts on Pest Complex. Beginning in the late fall of 2014 and continuing through winter and early spring of 2015, Walsh, Gent, and Barbour will establish research plots in their respective hop-growing regions of Washington, Oregon, and Idaho in which to conduct the studies on water and nutrient impacts to the pest complex. Irrigation engineer Peters, who designed the deficit irrigation systems for the previous SCRI, will consult on the system setup and configuration. In years 2-4, plant physiologist Griffith will conduct plant, cone, and soil nutrient analysis keyed to the various water and fertility regimes for analysis to be coordinated by Walsh. Also in years 2-4, fermentation scientist Shellhammer will conduct analytical measurements of chemical constituents of cones and brew beers to evaluate the impacts of the pest pressure and production regimes on brewing quality.Objective 2a: Thresholds for Mites and Aphids. Over the course of the project, utilizing existing and emerging data, entomologists Walsh and Barbour will develop a damage function and dynamic action threshold for spider mites and hop aphids based on key risk factors.Objective 2b: Molecular Diagnostics for Resistance. Beginning in the fall of 2014 and continuing throughout the project, molecular biologist and entomologist Lavine will expand robust molecular diagnostics including a comprehensive RNA-seq-based screen to identify resistance mechanisms from multiple populations of field-collected and laboratory selected spider mites (for bifenthrin, abamectin and bifenazate) and then develop quantitative PCR assays to predict acaricide resistance in the field.Objective 2c: Area-wide Powdery Mildew Management. Plant pathologist Gadoury's laboratory will be responsible for developing the basis of a predictive model for ascospore release in Podosphaera macularis, the causal agent of powdery mildew in hop. The model will address ascospore availability, release, and infection, and basic ecology of the ascigerious stage. This knowledge will be analyzed in cooperation with pathologist Gent and incorporated as a variable in a long-term, area-wide powdery mildew management strategy. Gent also will collect data and conduct analyses to develop a landscape-level understanding of where powdery mildew overwinters and how disease spreads among a network of hop yards.Objective 3: Heritability of Resistance Characteristics. Walsh, Gent, and Barbour, in consultation with industry specialist Miller and the stakeholder Advisory Panel, will select, among the 13 varieties of aroma hops of interest to craft brewers, several varieties known or likely to exhibit tolerance to spider mites, hop aphid, and downy and powdery mildews. In years 1 and 2 of the project, the team will conduct greenhouse trials on these varieties. In years 3 and 4 of the project, portions of the research plots established in WA, OR, and ID will be allocated to planting out the varieties/crosses identified in the greenhouse trials. Extension educator Miller concurrently will work with grower-cooperators in New York to plant out the varieties/crosses identified. Fermentation scientist Shellhammer will brew product from those varieties shown to possess arthropod pest and/or disease tolerance, elucidating flavor profiles and brewing qualities.Objective 4: Education Outreach. A variety of specific outreach activities are planned. These are elucidated in item 6 of this section.Objective 5: Outcome Assessment. Agricultural economist Marsh will translate quality changes resulting from abiotic manipulation factors (water and nutrients) and the brewing characteristics of the resistant varieties into market impacts. Marsh will further study the interactions of economic thresholds, pest/disease management, and MRLs in an economic modeling context. Sociologist Sherman will continue her work in the rural communities of PNW hop-growing regions, conducting qualitative interviews to determine perceptions, choices, and impacts of pest management and related crop production choices. Further discussion of outcome assessment is presented under item 5 of this section, Means of Analysis/Assessment/Interpretation.Objective 6: Student Involvement. Walsh, Gadoury, Marsh, Shellhammer, and Lavine will mentor PhD students and task them with specific research and extension roles as presented in the following section, beginning with the winter 2015 term and continuing throughout the remaining 3.5 years of the project. Nearly all other project participants will be involved with mentoring graduate or undergraduate students in some capacity.Project Management/Stakeholder Input. Communication specialist O'Neal will act as overall project manager, coordinating activities between the PD, co-PIs, Key Personnel, and the stakeholder Advisory Panel as required. She will provide support and direction for the outreach activities as described in item 6, following. A cross-section of team members, including PD Walsh, will attend semi-annual Hop Research Council meetings, usually in January and August, as well as other regularly scheduled hop industry meetings in June and October of each year. Formal consultation with the project Advisory Panel will take place at least twice annually.

Progress 09/01/14 to 08/31/19

Outputs
Target Audience:Target audiences reached during the course of this project included hop growers (regionally, nationally, and internationally, brewers andother stakeholders in the hop and brewing industries, researchers working on integrated pest managment in hop and other crops, and students of entomology and plant pathology. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?In addition to providing professional development via information dissemination to hop growers, brewers, and other primary stakeholders by presenting our findings in print and orally (see "How have the results been disseminated to communities of interest"), Co-PDs and their graduate students provided and received professional development by participating in scientific conferences in their individual disciplines (economics, entomology, sociology, plant pathology. Numerous graduate, post-graduate, undergraduate, and even high school students were mentored during the course of this project and have been named individually in our Progress Reports for project years 1-4. In the project's final year, the following students played a key role in carrying out the research and extension objectives and received mentorship, training, and professional development: Entomologist and PD Doug Walsh's PhD student Adekunle Adesanya completed his degree just prior to this reporting period but continued to publish a final journal article on his work pertaining to this project in 2019. He went on to employment in his field in a postdoctoral program Plant Pathologist and Co-PD David Gadoury's PhD student Bill Weldon also completed his degree and published and extensively in this reporting period. Hewas instrumental in development of the powdery mildew studies and the extension of their results. Sociologist and Co-PD Jennifer Sherman's PhD student Jordan Burke worked on field research, interview transcription, and publication development, publishing one peer-reviewed journal article during this reporting period and beginning preparation of another to be submitted in late 2019 for 2020 publication. Plant Pathologist and Co-PD David Gent mentored four students during this reporting period:Anne Iskra, graduate research assistant (seeking MS);Cameron Ross, graduate research assistant (seeking MS);Trevor Clark, high school student research assistant (seeking AA); andLauren Komnenus, undergraduate research assistant (seeking BS). Fermentation Scientist and Co-PD Thomas Shellhammer mentored numerous graduate and undergraduate students and research assistants during this reporting period, several of whom published journal articles, made oral presentations at conferences or other stakeholder venues, and/or presented posters at conferences. All were involved in a meaningful way with research and/or outreach pursuant to this project.Graduate research assistants:Scott Lafontaine, Ph.D. candidate;Kaylyn Kirkpatrick, M.S. candidate;Dean Hauser, M.S. candidate;Lindsey Rubottom, M.S. candidate;Karli Van Simaeys, M.S. candidate;Arnbjorn Stokholm, M.S. candidate.Undergraduate research assistants:Tristan Reynolds, Undergraduate summer researcher;Mason Klaus, Hops chemistry analyst;Jordan Chulyak, Hops chemistry analyst;Drake Graham, Hops chemistry analyst;Silas Shanafeld, Pilot Research Brewery assistant;Richard Molitor, Hops chemistry analyst & investigation of hops/yeast interactions;Lucy Bauer, Hops chemistry analyst;Arnbjorn Stockholm, Hops chemistry analyst & investigation of beer hazes in dry-hopped beers;Maika Watanabe, Pilot Research Brewery assistant;Ben Smallen, Pilot Research Brewery assistant;Nick Spatafora, Hops chemistry analyst & investigation of hops/yeast interactions;Andrew Sutton, Pilot Research Brewery assistant and Head Brewer;Sydney Lee, Pilot Research Brewery assistant and Head Brewer. How have the results been disseminated to communities of interest?Specific publications and other outputs have been cited in the "Products" and "Other Products" section of this project's REEport Progress Reports for each project year. Outputs for the final year of this project are cited in the Products and Other Products section of this Final Report. In summary, numerous scientific journal articles were written and published, scores of presentations were made at state hop commission meetings, oral and poster presentations were made at regional, national, and international hop and brewing conferences (e.g., American Hop Convention, Great Lakes Hop & Barley Conference, Craft Brewers Conference & BrewExpo America, Beeronomics Conference, European Brewing Congress Convention) as well as at scientific conferences (e.g., American Phytopathological Society, Entomological Society of America, American Society of Brewing Chemists). Web content was developed, maintained, and expandedon university and industry websites. Videos were produced and made available to stakeholders. Extension publications were produced highlighting research resulting from this project. Throughout the course of the project, hop growers and brewers were engaged invididually and collectively as participants in the research, including those grower-cooperators who allowed us to set up experiments within their commercial fields, those brewers who helped in sensory evaluation and brewing of beers from hops exposed to varying treatments, and growers who provided samples of hop plants and cones impacted by the arthropod and disease pests on which we were focused. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? Obj. 1.A multi-year field study evaluated the influence of nitrogen fertilization rate and timing on cone quality and nitrate accumulation in cones. Findings varied by year, but generallyalpha-acids, beta-acids, and total oil volume decreased linearly with increasing nitrogen ratewhile cone color (degree of greenness)and nitrate content of cones increased linearly with nitrogen rate. Yield was not improved with the highest nitrogen rate. In one of four studies, panelists used triangle tests to evaluate aroma of ground hop cones and detected a difference among treatments. Alpha- and beta-acids decreased and nitrate concentration increased when nitrogen was applied after bloom. Overall, this research indicates that applying the lowest feasible nitrogen rate and ceasing nitrogen applications before or at bloom may optimize certain cone quality factors and minimizenitrate accumulation. Regarding water level, data indicate that powdery mildew levels can be reduced via early season water stress, but yields were impacted. Obj. 2a.We analyzed historical data collected from 2005 to 2018 and identified risk factors associated with infestation of hop cones by twospotted spider mite (TSSM) and developed two probabilistic risk algorithms for predicting when TSSM may damage cones. The models consider abundance of TSSM during cone development in the upper foliage canopy or the ratio of mites to predatory arthropods from mid-July through harvest. The abundance-based model predicted damage with 83% accuracy when damage did occur and 96% accuracy when damage did not occur. Key finding: Timing of TSSM occurence relative to cone development is important for understanding the risk of cone damage, but in the inverse, i.e.high population levels of twospotted spider mite in the spring either had no association or a negative association with the risk of cone damage at harvest. We also found that biocontrol agents (beneficial predators of TSSM are resilient to variation in fertilization regimes and resilient in the year after application of a broad-spectrum pesticide (but not the year of application). Obj. 2b. Field-collected TSSM were evaluated for both phenotypicresistance and resistance genotypes to various acaricides. Many field populations exhibited multiple resistance pathways. We detected high expression of resistance-associated detoxification belonging to cytochrome P450s, glutathione S transferases, and carboxylesterases. Mutations occurred most frequently across the target sites of I1017F in chitin synthase 1 gene (97%), G126S in cytochrome b (85.7%), and F1538I in the voltage-gated sodium channel gene (100%). These findings, coupled with recent advances in rapid, cost-effective, in-field molecular detection methods, have paved the way to a practical resistance detection platform now under development. Obj. 2c.We formulated a model of powdery mildew (PM) pathogen dispersal during spring and early summer at the intermediate scale between synoptic weather systems and microclimate (mesoscale) based on a census of commercial hop yards in western Oregonduring 2014 to 2017. For the regions east of the Rockies, where the disease has a sexual reproduction component, we studied seasonal distribution of PM ascospore release for populations in New York (2018-2019), North Carolina (2019), and Wisconsin (2019), providing data from regions with winters varying from highly temperate to highly cold and snowy.Samples of hop PMwere taken from across the US, including commercial plantings in the PNW, Midwest, and Northeast as well as feral hops. All samples underwent DNA extraction and were subjected to qPCR primers for both mating types, resulting in a distribution map.Experiments were also conducted assessing the ability of PM ascospores to remain viable and infectious under higher temperatures (such as those associated with cone drying as well as during seed vernalization) and low temperatures (when subjected to acute cold events). Obj. 3. The USDA-ARS advanced cycle germplasm was relocated from private land to WSU Prosser IAREC in fall of 2017 and fully re-established in 2018. A systemic evaluation of PM reaction was completed for publicly available male hop germplasm in this collection. Iterative inoculations with 3 isolates of PM fungus with varying race identified 23 accessions (16.9% of those tested) with apparent resistance to all known races of the pathogen present in the PNW. Of these, 12 were resistant when inoculated with 3 additional isolates obtained from Europe with novel virulences. This work was completed in 2018. Identification of possible sources of PM resistance, novel and otherwise, will be useful to hop breeding programs moving forward. Obj. 4. See How Have Results Been Disseminated to Communities of Interest Obj. 5. Summaries of project activity are presented by scientific discipline: Physical Science. Hops produced under the production variables of Obj's 1 and 2 were analyzed chemically and sensorily, as were beers brewed from these hops. Temperature variables were also studied in the project's final year. Data impacting hop quality matriceshavebeen analyzed and results provided to stakeholders. Economics. Studies and publications included: pesticide substitution in hop under Maximum Residue Limits; the beer industry as a case study for divestiture impact on mergers; hop pricing; risk management for microbreweries; and interaction of restricted and unrestricted chemical use in hop. Sociology. It had been suggested by stakeholders (including within the most recent hop Pest Management Strategic Plan) that management efforts in hop might benefit from, or even require, cooperation beyond the boundaries of individual farms.Our sociological focus for this project was, therefore, discerning the barriers to adoption of cooperative pest and hop yard management. In-depth, one-on-one interviews with hop producers were undertaken in the first 3 years of the project, transcribed and analyzed in the 4th year, andsummarized for publication in the final year.Findings indicated that hop growers were generally open to communicating and cooperating with neighboring growers with respect to disease incidence and, to some extent, management tactics, but reluctance to communicate/cooperate increased with respect to information they considered proprietary and also when recipients of the information were unknown to them and/or at a greater distance.In the end, developing a reporting system and coordinated management efforts with producers beyond the neighbor-to-neighbor scale would require formalized structures designed to provide assurance of anonymity, consitence in data collection, reciprocation, and sanctions for use of information in ways that could damage participants or provide unfair advantage. That being said, results indicate a potential for collective action in management of diseases and other pests, but with limitations on the scope and nature of the collaboration. Obj. 6. See Opportunities for Training and Professional Development

Publications

  • Type: Other Status: Published Year Published: 2019 Citation: Gent, D.H., B. Claassen, M. Wiseman, and L. Santamaria. 2019. Managing Powdery Mildew in Hop: Best Practices. Oregon State University Extension Service, EM 9256. 6 pp. https://catalog.extension.oregonstate.edu/sites/catalog/files/project/pdf/em9256.pdf
  • Type: Journal Articles Status: Published Year Published: 2019 Citation: Weldon, WA., Palumbo, CD., Kovaleski, AP., Tancos, K., Gadoury, DM., Osier, MV., Cadle-Davidson, L. 2019. Transcriptomic profiling of acute cold stress-induced disease resistance (SIDR) genes and pathways in the grapevine powdery mildew pathosystem. Mol Plant Microbe Interact doi: 10.1094/MPMI-07-19-0183-R
  • Type: Journal Articles Status: Other Year Published: 2020 Citation: Burke, J., and J. Sherman. In prep. The Latent Environmental Effects of Foreign Food Safety Standards and Hop Growing in the Pacific Northwest. Submitting to Environmental Sociology in late fall 2019.
  • Type: Journal Articles Status: Published Year Published: 2019 Citation: Barbour, J.D., D.G Alston, D.B Walsh, M. Pace, & L.M. Hanks. 2019. Mating Disruption for Managing Prionus californicus (Coleoptera: Cerambycidae) in Hop and Sweet Cherry. J. Econ Entomol. https://doi.org/10.1093/jee/toy430
  • Type: Journal Articles Status: Published Year Published: 2018 Citation: Wu M, Adesanya AW, Morales MA, Walsh D, Lavine L, Lavine M, Zhu F. 2018 Multiple acaricides resistance and underlying mechanisms in Tetranychus urticae on hops. J.Pest Sci. https://doi.org/10.1007/s10340-018-1050-5
  • Type: Journal Articles Status: Published Year Published: 2019 Citation: Iskra, A.E., Lafontaine, S.R., Trippe, K.M., Massie, S.T., Phillips, C.L., Twomey, M.C., Shellhammer, T.H., and Gent, H.D. 2019. Influence of nitrogen fertility practices on hop cone quality, Journal of American Society of Brewing Chemists, 77(3), pp. 199-209. https://doi.org/10.1080/03610470.2019.1616276
  • Type: Journal Articles Status: Published Year Published: 2019 Citation: Iskra, A. E., Woods, J. L., and Gent, D. H. 2019. Stability and resiliency of biological control of the twospotted spider mite (Acari: Tetranychidae) in hop. Environmental Entomomology doi: 10.1093/ee/nvz071
  • Type: Journal Articles Status: Published Year Published: 2019 Citation: Sherman, J., Burke, J. M., and Gent, D. H. 2019. Cooperation and coordination in plant disease management. Phytopathology https://doi.org/10.1094/PHYTO-01-19-0010-R
  • Type: Journal Articles Status: Published Year Published: 2019 Citation: Gent, D. H., Bhattacharyya, S., and Ruiz, T. 2019. Prediction of spread and regional development of hop powdery mildew: A network analysis. Phytopathology 109:1392-1403.
  • Type: Journal Articles Status: Published Year Published: 2019 Citation: Hauser, D.G., Lafontaine, S.R., and Shellhammer. T.H. 2019. The extraction efficiency of dry-hopping. Journal of American Society of Brewing Chemists, 77(3), pp. 188-198. https://doi.org/10.1080/03610470.2019.1617622
  • Type: Journal Articles Status: Published Year Published: 2019 Citation: Barnette, B.M. and Shellhammer, T.H. 2019. Evaluating the impact of dissolved oxygen and aging on the dry-hopped aroma stability in beer, Journal of American Society of brewing Chemists, 77(3), pp. 179-187. https://doi.org/10.1080/03610470.2019.1603002
  • Type: Journal Articles Status: Published Year Published: 2019 Citation: Hauser, D.G., Stokholm, A., and Shellhammer. T.H. 2019 Investigating the potential for re-using spent dry-hops in the brew kettle, BrewingScience, May/June, pp. 125-131. https://doi.org/10.23763/BrSc19-14hauser
  • Type: Journal Articles Status: Published Year Published: 2019 Citation: Lafontaine, S.R., and Shellhammer, T.H. 2019. Investigating the factors impacting the aroma, flavor, and stability in dry-hopped beers, MBAA Technical Quarterly, 56(1), 13-23. https://doi.org/10.1094/TQ-56-1-0225-01
  • Type: Journal Articles Status: Published Year Published: 2019 Citation: Lafontaine, S.R., and Shellhammer, T.H. 2019. How hoppy beer production has redefined hop quality and a discussion of agricultural and processing strategies to promote it, MBAA Technical Quarterly, 56(1), 1-12. https://doi.org/10.1094/TQ-56-1-0221-01
  • Type: Journal Articles Status: Other Year Published: 2019 Citation: Weldon, WA., Ulrich, MR., Smart, LB., Smart, CD., Gadoury, DM. (September 2019) Cross infectivity of powdery mildew isolates originating from Japanese hop (Humulus japonicus) and Industrial hemp (Cannabis sativa) in New York. In preparation.
  • Type: Journal Articles Status: Published Year Published: 2018 Citation: Kirkpatrick, K.R. and Shellhammer, T.H. 2018. A cultivar-based screening of hops for dextrin degrading enzymatic potential, Journal of American Society of brewing Chemists, 76(4), pp. 247-256. https://doi.org/10.1080/03610470.2018.1546091
  • Type: Journal Articles Status: Published Year Published: 2018 Citation: Lafontaine, S. R., Varnum, S., Roland, A., Delpech, S., Dagan, L., Vollmer, D.M., Kishimoto, T. and Shellhammer, T.H. 2018. Impact of harvest maturity on the aroma characteristics and chemistry of Cascade hops during dry-hopping. Journal of Food Chemistry. https://doi.org/10.1016/j.foodchem.2018.10.148
  • Type: Other Status: Published Year Published: 2019 Citation: Woods, J. L., Iskra, A. E., James, D. G., and Gent, D. H. La promoci�n de la conservaci�n del control biol�gico de los �caros en l�pulo. Oregon State University, Corvallis, Oregon.
  • Type: Other Status: Published Year Published: 2019 Citation: Woods, J. L., Iskra, A. E., James, D. G., and Gent, D. H. Enemigos naturales de �caros de dos puntos y pulg�n de l�pulo en l�pulo. Oregon State University, Corvallis, Oregon.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Gent, D. H. 2019. Nitrogen application timing effects on nitrate accumulation in hop cones, yield, and cone quality factors. Annual Report of the Hop Research Council, Hubbard, Oregon.
  • Type: Journal Articles Status: Published Year Published: 2018 Citation: Vollmer, D.M., Lafontaine, S. R. and Shellhammer, T.H. 2018. Aroma extract dilution analysis of beers dry-hopped with Cascade, Chinook, and Centennial. Journal of American Society of Brewing Chemists, 76(3), pp. 190-198. https://doi.org/10.1080/03610470.2018.1487746
  • Type: Journal Articles Status: Published Year Published: 2018 Citation: Lafontaine, S. R. and Shellhammer, T. H. 2018. Sensory directed mixture study of beers dry-hopped with Cascade, Centennial, and Chinook. Journal of American Society of brewing Chemists, 76(3), pp. 109-208. https://doi.org/10.1080/03610470.2018.1487747
  • Type: Journal Articles Status: Published Year Published: 2018 Citation: Gent, D. H., Claassen, B. J., Twomey, M. C., and Wolfenbarger, S. N. 2018. Identification of resistance to powdery mildew in male hop germplasm. Plant Health Progress. doi:10.1094/PHP-05-18-0027-RS.
  • Type: Other Status: Published Year Published: 2019 Citation: Woods, J. L., Iskra, A. E., James, D. G., and Gent, D. H. Natural enemies of two-spotted spider mite and hop aphid on hop. Oregon State University, Corvallis, Oregon.
  • Type: Other Status: Published Year Published: 2019 Citation: Woods, J. L., Iskra, A. E., James, D. G., and Gent, D. H. Promoting conservation biological control of spider mites in hop. Oregon State University, Corvallis, Oregon.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Shellhammer, T.H., Rubottom, L., Lafontaine, S.R., and Hauser, D. 2019. Evaluating kilning influences on the brewing quality of hops. Technical report to the Hop Research Council. 20 pages.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Walsh, D.B. 2019. Update on arthropod management in hop. Summer Meeting of the Hop Research Council, 16 July, Boise, ID.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Rubottom, L., Lafontaine, S.R. and Shellhammer, T.H. 2019. Impact of harvest maturity and kiln temperature on aroma hop quality. Summer Meeting of the Hop Research Council, 16 July, Boise, ID.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Shellhammer, T.H. 2019. Hop-derived enzymes and dry-hop creep, MBAA District Northwest semiannual meeting, Hood River, May 10.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Shellhammer, T.H. 2019. Independent Brewers Association Mashup with Dr. Tom Shellhammer, lecture on hops and beer quality with a focus on dry-hopping, Wayward Brewing Company, Sydney, Australia May 3.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Shellhammer, T.H. 2019. Independent Brewers Association Mashup with Dr. Tom Shellhammer, lecture on hops and beer quality with a focus on dry-hopping, Felons Brewing Company, Brisbane, Australia May 2.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Shellhammer, T.H. 2019. Independent Brewers Association Mashup with Dr. Tom Shellhammer, lecture on hops and beer quality with a focus on dry-hopping, Moon Dog Craft Brewery, Melbourne, Australia May 1.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Shellhammer, T.H. 2019. Hops and beer quality, what affects it, what it is and what it isnt. Tasmanian Fresh Hop Festival, Launceston, Tasmania, Australia, April 26-28.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Shellhammer, T.H. 2019. How, why and when to use fresh hops, the long learning curve. Tasmanian Fresh Hop Festival, Launceston, Tasmania, Australia, April 26-28.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Shellhammer, T.H. 2019. Australian brewing, lessons from the PNW. Tasmanian Fresh Hop Festival, Launceston, Tasmania, Australia, April 26-28.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Weldon, B, L. Cadle-Davidson, D.H. Gent, S. Wolfenbarger, B.J. Knaus, N.J. Gr�nwald, and D.M. Gadoury. Proceedings of the International Congress of Plant Pathology 2018. AmpSeq based SNP marker development for population analysis of geographically diverse isolates of hop powdery mildew (Podosphaera macularis). August 2018.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Gent, D. H. 2019. Towards a new understanding and risk management of the mildews. Summer Meeting of the Hop Research Council, 17 July, Boise, ID.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Gent, D. H. 2019. Cone diseases and quality issues: causes, consequences, and management. Oregon Hop Commission. March 21, St. Paul, OR.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Shellhammer, T.H. 2019. Dry-hopping to achieve intense hop aromas&and some unintended consequences. Michigan Brewers Guild and MBAA conference, Kalamazoo, MI, January 10 - 12.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Shellhammer, T.H. 2019. Rethinking the Contributions of Hops to Beer Flavor. Ohio Crafter Brewers Association Annual Meeting, Columbus, OH, January 9 - 11.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Weldon, WA., Palumbo, CD., Kovaleski, AP., Tancos, K., Gadoury, DM., Osier, MV., Cadle-Davidson, L. Cold Shock  Uncovering transcriptional changes driving a model for stress-related disease resistance. APS 2019 National Meeting Abstracts.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Weldon, WA., Ullrich MR., Smart, LB., Smart, CD., Gadoury, DM. (2019 APS National Meeting). Cross infectivity of powdery mildew isolates originating from Japanese hop (Humulus japonicus) and Industrial hemp (Cannabis sativa) in New York. August 2019. poster
  • Type: Other Status: Published Year Published: 2019 Citation: Weldon, B., Marks, M., Gadoury, DM., Gevens, A. (UW-Madison Vegetable Crop Updates  Update 5). Hop powdery mildew pathogen disease cycle. May 24, 2019.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Gent, D. H. 2019. Hop cone diseases: diagnosis and management. Wilbur Ellis grower meeting. February 8, Woodburn, OR.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Walsh, D.B. 2019. Arthropod management update. Washington Hop Industry Annual Meeting, 4 January, Yakima, WA.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Gent, D. H. 2019. Powdery mildew fungicide update. Washington Hop Industry Annual Meeting, 4 January, Yakima, WA.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Gent, D. H. 2019. Diversity and origin of powdery mildew in the Pacific Northwest: implications for spread. Washington Hop Industry Annual Meeting, 4 January, Yakima, WA.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Claasen, B. J., and Gent, D. H. 2019. Matching fungicide physical mode of action to improve powdery mildew management. Washington Hop Industry Annual Meeting, 4 January, Yakima, WA.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Iskra, A. E., and Gent, D. H. 2019. The development and disruption of biological control. Washington Hop Industry Annual Meeting, 4 January, Yakima, WA.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Wiseman, M., and Gent, D. H. 2019. Potential revisions to the hop powdery mildew risk index for Cascade. Washington Hop Industry Annual Meeting, 4 January, Yakima, WA.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Woods, J. L., and Gent, D. H. 2019. Risk factors for and prediction of mite damage to cones. Washington Hop Industry Annual Meeting, 4 January, Yakima, WA.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Shellhammer, T.H. and Lafontaine, S.R. 2019. Understanding the chemical drivers of the International Bitterness Unit in highly hopped beer. Oral presentation #11 at the American Society of Brewing Chemists Annual Meeting, New Orleans, LA, June 24 - 26.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Salanouve, E., Delpech S., Viel C., Lafontaine S. R., Shellhammer, T.H. and Dagan, L. 2019. Dimethyl sulfide in beer: the potential role of hops, Oral presentation at the 37th Congress of the European Brewing Convention, Antwerp, Belgium, June 2 - 5.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Rubottom, L., Lafontaine, S.L. and Shellhammer, T.H. 2019. Hauser, D.G. and Shellhammer, T.H. 2019. A comparison of single-stage and two-stage dry-hopping regimes. Oral presentation #16 at the American Society of Brewing Chemists Annual Meeting, New Orleans, LA, June 24 - 26.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Dagan, L., Delpech S., Viel C., Lafontaine S. R., Shellhammer, T.H. and Salanouve, E., 2019. Dimethyl sulfide in beer: the potential role of hops, Oral presentation #21 at the American Society of Brewing Chemists Annual Meeting, New Orleans, LA, June 24 - 26.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Hauser, D.G. and Shellhammer, T.H. 2019. A comparison of single-stage and two-stage dry-hopping regimes. Poster presentation #31 at the American Society of Brewing Chemists Annual Meeting, New Orleans, LA, June 24 - 26.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Lafontaine S. R. and Shellhammer, T.H. 2019. Blending Cascade, Centennial, and Chinook hops to create dry-hopping, Poster presentation at the 37th Congress of the European Brewing Convention, Antwerp, Belgium, June 2 - 5.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Lafontaine S. R., Rubottom, L., Hauser, D. and Shellhammer, T.H. 2019. Impact of kilning temperatures on the enzymic potential of hops. Poster presentation #67 at the American Society of Brewing Chemists Annual Meeting, New Orleans, LA, June 24 - 26.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Stokholm, A., Hauser, D.G., Harrison, K.R. and Shellhammer, T.H. 2019. Dry hopping and vicinal diketones: Observations of hop-induced refermentation and associated diacetyl production. Poster presentation #72 at the American Society of Brewing Chemists Annual Meeting, New Orleans, LA, June 24 - 26.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Van Simaey, K.R. and Shellhammer, T.H. 2019. Lafontaine S. R., Rubottom, L., Hauser, D. and Shellhammer, T.H. 2019. Impact of kilning temperatures on the enzymic potential of hops. Poster presentation #87 at the American Society of Brewing Chemists Annual Meeting, New Orleans, LA, June 24 - 26.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Lafontaine S. R., Rubottom, L., Hauser, D. and Shellhammer, T.H. 2019. Impact of kilning temperatures on the aroma potential of hops, Poster presentation at the 37th Congress of the European Brewing Convention, Antwerp, Belgium, June 2 - 5.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Shellhammer, T.H., 2019. Hop-derived dextrin-reducing enzymes from dry-hopping  does variety matter? Oral presentation at the Craft Brewers Conference, Denver, CO April 8  11.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Walsh, D.B. 2019. Advances in integrated arthropod control on hop: 2018. Oral presentation at the 2019 American Hop Convention/Hop Research Council Winter Meeting, Monterey, CA, January 22  24.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Rubottom, L., Lafontaine, S. R., and Shellhammer, T.H. 2019. Evaluating the kilning influences on the brewing quality of hops. Oral presentation at the 2019 American Hop Convention/Hop Research Council Winter Meeting, Monterey, CA, January 22  24.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Barnette, B. and Shellhammer, T.H. 2019. The instability of dry-hop flavor and aroma in beer. Poster presentation at the 2019 American Hop Convention/Hop Research Council Winter Meeting, Monterey, CA, January 22  24.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Lafontaine, S. R., Varnum, S., Roland, A., Delpech, S., Dagan, L., Vollmer, D.M., Kishimoto, T. and Shellhammer, T.H. 2019. Impact of harvest maturity on the aroma characteristics and chemistry of Cascade hops. Poster presentation at the 2019 American Hop Convention/Hop Research Council Winter Meeting, Monterey, CA, January 22  24.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Kirkpatrick K.R. and Shellhammer, T.H. 2018. Characterizing the diastatic activity of hops in dry-hopped beers. Oral Presentation at the Young Scientist Symposium on Malting, Brewing and Distilling. Bitburg, Germany, September 12 - 14.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Hauser, D. and Shellhammer, T.H. 2018. The fate of hop volatiles during dry-hopping. Oral Presentation at the Young Scientist Symposium on Malting, Brewing and Distilling. Bitburg, Germany, September 12 - 14.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Lafontaine, S.R. and Shellhammer, T.H. 2018. Impact of harvest maturity on the aroma characteristics and chemistry of Cascade hops. Poster Presentation at the Young Scientist Symposium on Malting, Brewing and Distilling. Bitburg, Germany, September 12 - 14.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Lafontaine, S., Hauser, D., Foster, R., Donaldson, J., Gamache, D., Shellhammer, T.H. 2018. Impact of kiln temperatures on the aroma and enzymatic potential of hops during dry-hopping. EBC Symposium: Recent Advances in Hop Science. N�rnberg, Germany, September 10 & 11.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Shellhammer, T.H. and Lafontaine, S. 2018. Influences of beer chemistry on the Bitterness Unit. EBC Symposium: Recent Advances in Hop Science. N�rnberg, Germany, September 10 & 11.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Shellhammer, T.H. 2018. Sensorial analyses of dry-hopped beers produced with advanced technology. Jean De Clerck Chair XVI, Universit� catholique de Louvain, Louvain-la-Neuve, Belgium, September 2  5. (invited)
  • Type: Websites Status: Published Year Published: 2019 Citation: Cornell College of Agriculture and Life Sciences, School of Integrative Plant Science: Hops. 2019. Website maintenance, expansion, and transition to ADA compliance. https://sips.cals.cornell.edu/extension-outreach/hops/
  • Type: Websites Status: Published Year Published: 2019 Citation: Washington State University Integrated Pest Management: Hops. 2019. Website maintenance. https://ipm.wsu.edu/specialty-crops/hops/
  • Type: Websites Status: Published Year Published: 2019 Citation: Hop Growers of America. 2019. Website content expansion, updating, maintenance. http://usahops.org


Progress 09/01/17 to 08/31/18

Outputs
Target Audience:Our activities and outreach during this reporting period reached hop growers (nationally and internationally), other stakeholders in the hop and brewing industries,researchers working on integrated pest (arthropod and disease) management in hop, and entomology and plant pathology students. Changes/Problems:We are grateful to have received a no-cost extension to continue our course of research and extension for one additional year. While no major problems occurred, the year-to-year variability of agricultural production (e.g., extremely high yields in Yakima Valley hops in 2017) and the pest complex (e.g., unusually low levels of powdery mildew presence in New York hops in 2018) make it desirable to have an additional year of data to validate multi-year prediction models and prevention tactics, as well as time to develop additional outreach materials and scientific journal articles to reach more stakeholders with even more complete data and recommendations. What opportunities for training and professional development has the project provided?Numerous students were mentored during this reporting periodas a direct result of this project. These graduate, undergraduate, and even high school students played roles in field and laboratory research, participated in scientific conferences, and interacted with stakeholders. Doug Walsh, Washington State University, Project Director and Entomologist Haley Meirndorf, undergraduate research assistant Karina Cardenas, undergraduate research assistant Mariany Morales, undergraduate research assistant Elizabeth Franco,undergraduate research assistant Adekunle Adesanya, PhD Candidate, graduate research and extension assistant(NOTE: Adesanya received the John Henry Comstock award from the Entomological Society of America in 2018, the highest award a graduate student can receive from ESA. His research was funded by this SCRI Grant) Dave Gent, USDA-ARS/Oregon State University, Co-PD, Plant Pathologist Anne Iskra, graduate research assistant Cameron Ross, undergraduate research assistant Trevor Clark, high school student research assistant David Gadoury, Cornell University, Co-PD, Plant Pathologist Bill Weldon, PhD Candidate, graduate research and extension assistant Participants in Cornell College of Agriculture and Life Sciences Summer Research Scholars Program Camille Sisto, now a freshman in Bioinformatics at Rochester Institute of Technology (RIT) Cal Palumbo, now in the MS program at RIT Teddy Borlund, a senior at Colorado State University applying for graduate programs in Plant Pathology Thomas Marsh, Washington State University, Co-PD, Economist Xi Gu, PhD candidate, graduate assistant Jennifer Sherman, Washington State University, Co-PD, Sociologist Jordan Burke, PhD candidate, graduate assistant Thomas Shellhammer, Oregon State University, Co-PD, Fermentation Scientist Scott Lafontaine, PhD candidate, graduate research assistant Kaylyn Kirkpatrick, MS candidate, graduate research assistant Bradley Barnette, MScandidate, graduate research assistant Dean Hauser, MScandidate, graduate research assistant Dalton Behrens, undergraduate research assistant Alicia Collier, undergraduate research assistant Cameron McDaniel, undergraduate research assistant Ruth Nelson, undergraduate research assistant Lorena Ramos, undergraduate research assistant Ian Schacter, undergraduate research assistant Quinn Schmidt, undergraduate research assistant Ben Smallen, undergraduate research assistant Nic Spatafora, undergraduate research assistant How have the results been disseminated to communities of interest?In addition to formal presentations cited in the Products section of this report: All PDs have responded to telephone calls and emails from growers seeking pest management recommendations. Frequent two-way communication has been maintained with Hop Growers of America, the hop commissions in each state and region, the Hop Research Council, the Brewers Association, and the U.S. Hop Industry Plant Protection Committee. What do you plan to do during the next reporting period to accomplish the goals?Objective 1. As a follow-up to our Oregon studies on nitrogen timing, we plan to assess cones from our 2018 studies for additional factors including nitrate accumulation, brewing chemistry, and aroma. We will also complete our analysis of other impacts of nitrogen fertilizer timing that were underway at the writing of this report. The multi-year Washington studies on nitrogen rates and fertilization cutoff times will be finalized, with 2018 season data included and all data analyzed. Objective 2. Nutrient and water impact data from 2014-2018 will be correlated and final analyses performed. Flag shoot census will continue in Oregon and PM mapping conducted.The ascospore release assays will be repeated to further validate the prediction model. The acute overnight cold events tested in the laboratory will be taken to the field in fall of 2018. Due to limited number of samples available for the amplicon sequencing marker study in 2018, efforts will extend into 2019 to collect samples. Objective 5. From data generated by our sociological studies, three articles will be developed in the final reporting period: Cooperation and Competition among Hop Farmers will focus on barriers to coordination and cooperation as well as factors that facilitate it. Factors will include farm size and location and pre-existing relationships with industry and other growers. This article will likely be submitted toPlant Disease. Trust in IPM and Biological Control will delve into what our interviews revealed to be a vast variation in the level of trust among hop growers in principles of integrated pest management and the role of biological control in a successful and profitable hop farm. This article will likely be submitted toAgriculture and Human Values. Impact of Global Markets on Pesticide Usein the U.S. will focus on the relationship between global markets and regulations and U.S. hop producers' decisions in regard to pesticide use. This article will likely be submitted toEnvironmental Sociology.

Impacts
What was accomplished under these goals? Our work during this reporting period enabled our team to fine-tune recommendations to hop growers about management of critical pests and diseases. By integrating our findings with respect to nutrient inputs, irrigation, pesticide resistance, damage thresholds, and variety selection, growers can expect improved yields, crop quality, profitability, and global competitiveness. Objective 1. In OR, experiments continued to evaluate the impact of the timing (early, mid, late-season) of nitrogen (N) fertilizer applications on powdery mildew (PM), yield and cone quality factors. Measurements and evaluation are in progress. Preliminary data indicate that later timing of N application may increase levels of PM, decrease alpha-acids and delay maturation. Experiments continued to quantify impact of early spring water stress on PM development. Plots were established in a commercial yard in WA to test a broad range of production practices for timing the first irrigation of the season. Data thus far indicate that PM levels can be reduced in proportion to the duration of early season water stress, but yield was reduced by even short periods of water stress in early spring. Experiments on varying levels of N in Yakima Valley WA plots begun in 2013 have been repeated annually. For our September 2017 harvest, treating the fertilizer regimes, cutoff dates, and pesticide applications as stand-alone treatments, there were significant (p<0.05) differences in yield, with a trend for treatments with later fertilization cutoff (7/19/2017) to exhibit lower yields. The numerically superior treatment was 90 lbs. dry fertilizer with 150 lbs. applied via chemigation with a 6/21/2017 cutoff. Yields were extremely high in 2017. Data for 2018 are being collected. Arthropod abundance data from summer 2017 were analyzed during this reporting period (fall 2017).Pest mite abundance was low collectively throughout all the plots. While significant (p<0.05) differences were observed on several of the sample dates, the population density was too low to impact on plant performance or yield. Objective 2. Sampling was conducted in 8 commercial hop yards to provide independent data to validate the damage function derived in our studies to date. Studies were initiated to determine resiliency of biological control of spider mites to disturbances caused by excessive N fertilization and use of a broad-spectrum insecticide (bifenthrin).Experimental plots of cultivar Willamette were established in 2017 in a field where stable biological control of spider mites was established and damaging levels of the pest have not developed since 2008. A single application of bifenthrin was sufficient to disrupt biological control; severity of pest mite outbreak was proportional to N rate.Experiments continued into 2018 to quantify whether biological control redevelops after one season.To date, only low levels of spider mites have occurred, indicating that biological control can reestablish in one season following a severe mite outbreak.Yield and cone quality factors will be measured at harvest. 7 WA hop yards were monitored for arthropod abundance in 2018 and spray records were obtained. Mite abundance varied and was correlated to early season factors including application of disruptive pesticides and hop yard floor management practices. The intensive census of flag shoot incidence in hop yards was continued. Flag shoots are a key to overwintering and spread of PM in the Pacific Northwest (PNW). Findings indicate high correlation of thorough pruning with management of PM. Dispersal distances were mapped and a model has been created to assist in prediction of PM. Field and lab PM ascospore release assays were completed in NY. Correlation between duration of wetting periods across a range of temperatures and ascospore release was established in the laboratory, then used to generate a predictive model for percentage of total ascospore release across temperatures and wetting durations. Field data for 2018 fell within predicted periods. Chasmothecia are being generated to repeat these experiments spring 2019. Impact of acute overnight cold events on initial establishment of PM colonies was investigated for implications on early season management. In leaf assays, daily acute cold events of >1 hour at 4C or 4 hrs at 8C were demonstrated to significantly impact latency period and sporulation density/hyphal density of colonies. A similar delay in latency was confirmed in potted plants. Field tests pending. Amplicon sequencing molecular markers were developed that were capable of grouping isolates based on geography and, to some level, whether the hop was feral or commercial. Such markers can help us learn how new populations of PM are being introduced into Midwestern and Eastern US hop yards. Mating type of all isolates was determined and a distribution map created for samples collected in 2017. A lower than desirable number of samples were collectedin 2018, therefore efforts will continue into 2019. Toward assessing viability and infection risk for PM chasmothecia on hop seed, infested seed was collected, stratified and planted. While seed coats emerged and were documented in "risk spots" (such as continued attachment to coyledons), no PM was found in >300 seedlings. Objective 3. The USDA-ARS advanced cycle germplasm was relocated from a private grower site to WSU Prosser in fall of 2017; 2018 has been a critical re-establishment year. A systemic evaluation of PM reaction was completed for publicly available male hop germplasm in the USDA collection.Iterative inoculations with 3 isolates of PM fungus with varying race ID'd 23 (16.9%) accessions with apparent resistance to all known races of the pathogen present in the PNW.Of these, 12 were resistant when inoculated with 3 additional isolates obtained from Europe with novel virulences.The nature of resistance is unclear, but does not appear to be based on known R genes.Identification of possible novel sources of PM resistance will be useful to hop breeding programs. Objective 4. See How Have the Results Been Disseminated to Communities of Interest. Objective 5. Physical Science. Chemical, sensory and quality evaluations were conducted on hops from the WA and OR plots described in Obj 1 and beers brewed from these hops. Hops and beers from the fertilizer timing treatments were analyzed against those from 3 random Simcoe lots from the same farm. These 6 treatments were presented randomly to 61 panelists (growers, brewers) at the American Hop Convention, where they were asked to identify the presence of 45 sensory attributes. Only slight differences were found, statistically. Results indicate that fertilizer application timing has a minor impact on raw hop cone aroma quality. Physical Science.The role of input factors (oil composition/content, location, kilning) was studied relating to beer aroma performance in dry-hopped beer.Hop samples of 3 cultivars from 118 WA OR and ID hop yards across 3 years were analyzed for oil composition and sensorial impressions.Multiple linear regression analyses using the concentrations of 16 hop volatiles, total oil and harvest year effects identified specific volatiles to be more effective than total oil concentration in predicting aroma quality and intensity. Economic. Analysis of changes in pest management practices and subsequent hop production and marketing factors has resultedin publications and presentations listed in the Products section of this report. Sociological. Grower interviews were finalized in fall 2017. Transcript data from all years were analyzed to aid in understanding changes in pest management practices andpotential barriers to cooperation among producers as well as to document changes in knowledge, attitudes and behaviors. Data were coded spring and summer 2018. Sociological impacts are being developed into journal articles. Objective 6. See Opportunities for Training and Professional Development.

Publications

  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Adesanya, A., & D. Walsh. 2018 Persistent resistance; characterizing adaptation to xenobiotics in a generalist herbivore, Teteranchyus urticae. Comstock award acceptance speech. Pacific Branch Entomological Society of America. Reno, NV. June 2018.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Adesanya, A., M. Wu, L. Lavine, D. Walsh and F. Zhu. 2017. Acaricide resistance of the two- spotted spider mite in hop fields. Entomological Society of America, National meeting, Denver, Colorado.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Adesanya, A., M. Morales, L. Lavine, D. Walsh and F. Zhu. 2017. NADPH-cytochrome P450 reductase is involved in multiple acaricide resistance in the generalist herbivore, Tetranychus urticae Koch. Entomological Society of America, National meeting, Denver, Colorado.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: O'Neal, S. and D. Walsh. 2018. Integrated Pest Management of Arthropods on Hops: 2017 Report. American Hop Convention, January 2018, Palm Desert, CA.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Walsh, D. 2018. IPM on Hops. Hop Research Council, July 2018, Prosser, WA.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Walsh, D. 2017. Integrated Management of arthropod pests on hops. Beijing College of Agriculture, Beijing, China.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Walsh, D. 2018. Progress Report: Reducing the Impact of Industry-Critical Insect and Disease Problems in Hop through Development of Preventive and Predictive Strategies. Specialty Crop Research Initiative Project Director meeting, Washington DC, July 30, 2018.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Walsh, D. 2018. Biology and management of hops. Industry presentation made to three Yakima Chief audiences: Sunnyside, WA (May 15); Greenleaf, ID (May 16); Silverton, OR (May 17).
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Walsh, D. 2018. Acaricide tests on hops. Pacific Northwest Insect Control Conference, Portland, OR January 9, 2018.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Walsh, D. 2018. Mechanisms of resistance to ovicidal acaricides. Washington Hop Growers Association, Yakima, WA. January 6, 2018.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Walsh, D. 2018. New pests of hops. Washington Hop Growers Association, Yakima WA. January 6, 2018.
  • Type: Journal Articles Status: Accepted Year Published: 2018 Citation: Gent, D. H., Claassen, B. J., Twomey, M. C., and Wolfenbarger, S. N. 2018. Identification of resistance to powdery mildew in male hop germplasm. Plant Health Progress. In press.
  • Type: Journal Articles Status: Accepted Year Published: 2018 Citation: Gent, D. H., Mahaffee, W. F., Turechek, W. W., Ocamb, C. M., Twomey, M. C., Woods, J. L., and Probst, C. 2018. Risk factors for bud perennation of Podosphaera macularis on hop. Phytopathology. In press.
  • Type: Journal Articles Status: Published Year Published: 2018 Citation: Iskra, A. E., Woods, J. L., and Gent, D. H. 2018. Influence of nitrogen fertilization rate on hop looper. Journal of Economic Entomology doi.org/10.1093/jee/toy229
  • Type: Journal Articles Status: Published Year Published: 2018 Citation: Gent, D. H., Claassen, B. J., Twomey, M. C., Wolfenbarger, S. N., and Woods, J. L. 2018. Susceptibility of hop crown buds to powdery mildew and its relation to perennation of Podosphaera macularis. Plant Disease 102:1316-1325.
  • Type: Other Status: Published Year Published: 2017 Citation: Weldon, B., Gent, D. H. and Gadoury, D. M. 2017. Five considerations before ever planting your first hop. Cornell College of Agriculture and Life Sciences, Ithaca, New York. https://sips.cals.cornell.edu/sites/sips.cals.cornell.edu/files/shared/documents/intro.pdf
  • Type: Other Status: Published Year Published: 2017 Citation: Weldon, B., Gent, D. H. and Gadoury, D. M. 2017. Key differences and similarities in managing downy mildew vs. powdery mildew. Cornell College of Agriculture and Life Sciences, Ithaca, New York. https://sips.cals.cornell.edu/sites/sips.cals.cornell.edu/files/shared/documents/differences.pdf
  • Type: Other Status: Published Year Published: 2017 Citation: Weldon, B., Gent, D. H. and Gadoury, D. M. 2017. Scouting for powdery mildew: when, where, and how. Cornell College of Agriculture and Life Sciences, Ithaca, New York. https://sips.cals.cornell.edu/sites/sips.cals.cornell.edu/files/shared/documents/scouting-powdery.pdf
  • Type: Other Status: Published Year Published: 2017 Citation: Weldon, B., Gent, D. H. and Gadoury, D. M. 2017. Scouting for downy mildew: when, where, and how. Cornell College of Agriculture and Life Sciences, Ithaca, New York. https://sips.cals.cornell.edu/sites/sips.cals.cornell.edu/files/shared/documents/scouting-downy.pdf
  • Type: Other Status: Published Year Published: 2017 Citation: Weldon, B., Gadoury, D. M., and Gent, D. H. 2017. Management of downy mildewconsidering varietal resistance. Cornell College of Agriculture and Life Sciences, Ithaca, New York. https://sips.cals.cornell.edu/sites/sips.cals.cornell.edu/files/shared/documents/resistance.pdf
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Gent, D. H. 2018. Nitrogen application timing effects on nitrate accumulation in hop cones, yield, and cone quality factors. Annual Report of the Hop Research Council, Hubbard, Oregon.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Iskra, A. E., and Gent, D. H. 2018. Fundamentals of sampling for spider mites. Oregon Hop Commission, 20 July, Woodburn, OR.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Iskra, A. E., and Gent, D. H. 2018. Fundamentals of sampling for aphids. Oregon Hop Commission, 1 June, Hubbard, OR.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Iskra, A. E., and Gent, D. H. 2018. Nitrogen application timing effects on nitrate accumulation in hop cones, yield, and cone quality factors. Summer Meeting of the Hop Research Council, 24 July, Prosser, WA.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Gent, D. H. 2018. Towards a new understanding and risk management of the mildews. Summer Meeting of the Hop Research Council, 24 July, Prosser, WA.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Gent, D. H. 2018. Disease management updates and planning for 2018. Oregon Hop Commission, 15 April, St. Paul, OR.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Gent, D. H. 2018. Powdery mildew: damage, dissemination, and best management practices. Great Lakes Hop and Barley Conference, 13 March, Kalamazoo, MI.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Gent, D. H. 2018. Premade disease: just add water. D and M Chem Grower Meeting, 8 February, Yakima, WA.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Gent, D. H. 2018. From the ground up: our understanding of the seasonal progression of powdery mildew. Winter Meeting of the Hop Research Council, 24 January, Palm Desert, CA.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Claassen, B. J. and Gent, D. H. 2018. Management of downy mildew in light of multiple fungicide resistance. Winter Meeting of the Hop Research Council, 24 January, Palm Desert, CA.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Iskra, A. E. and Gent, D. H. 2018. The intersection of nitrogen fertility, pest management, and cone quality. Winter Meeting of the Hop Research Council, 24 January, Palm Desert, CA.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Gent, D. H. 2018. Irrigation, yield, and disease management in hops. GS Long Grower Meeting, 17 January, Yakima, WA.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Iskra, A. E., and Gent, D. H. 2018. The intersection of nitrogen fertilization, pest management, and hop cone quality. GS Long Grower Meeting, 17 January, Yakima, WA.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Gent, D. H. 2018. Early season irrigation, powdery mildew, and yield: some early results. Washington Hop Industry Annual Meeting, 5 January, Yakima, WA.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Iskra, A. E., and Gent, D. H. 2018. The intersection of nitrogen fertilization, pest management, and hop cone quality. Washington Hop Industry Annual Meeting, 5 January, Yakima, WA.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Gent, D. H. 2017. Cone quality issues and disease: causes, consequences, and management. Cornell Hops Conference, 2 December, Morrisville, NY.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Gent, D. H. 2017. Powdery mildew overwintering and disease spread. Oregon Hop Commission, 16 November, Aurora, OR.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Weldon, B. and D M Gadoury. 2018. Furthering the epidemiological understanding of hop powdery mildew (Podosphaera macular). overwintering and early season infection. Cornell AgriTech Research Symposium, June 2018.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Iskra, A. E. and Gent, D. H. 2017. Nitrogen fertility: influences on pests, mildew, and cone quality factors. Oregon Hop Commission, 16 November, Aurora, OR.
  • Type: Journal Articles Status: Published Year Published: 2018 Citation: Marks, M, Pauline Geske, A, Weldon, B, Gadoury, D.M. & Jane Gevens, A. (2018). Re-emergence of hop powdery mildew Podosphaera macularis in Wisconsin. Plant Disease. 10.1094/PDIS-12-17-1936-PDN.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Shellhammer, T.H., Lafontaine, S.R., and Pereira, C. 2017. Identifying brewing qualities which aid hop breeding: Examining hop oil content and its influence on dry-hop aroma in beer. Technical report to the Hop Research Council. 31 pages.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Shellhammer, T.H., Lafontaine, S.R., and Pereira, C. 2017. Examining hop oil content and its influence on dry-hop aroma in beer and a look at preliminary studies on the impact of kilning temperature on hop quality. Summer Meeting of the Hop Research Council, 24 July, Prosser, WA.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Shellhammer, T.H. 2018. Late Hopping Chemistry. Oral presentation at the Brewing Summit, San Diego, CA, August 12  15.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Lafontaine, S.R. and Shellhammer, T.H. 2018. Examination of factors that predict the dry-hop aroma performance of hops in beer. Oral presentation at the Brewing Summit, San Diego, CA, August 12  15.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Hauser, D., Lafontaine, S.R. and Shellhammer, T.H. 2018. The Extraction Efficiency of Hop Bitter Acids and Volatiles During Dry-Hopping. Oral presentation at the Brewing Summit, San Diego, CA, August 12  15.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Sharp, D., Lafontaine, S.R., and Shellhammer, T.H., 2018. Dry-hopping Beer and Achieving Consistent Flavor. Oral presentation at the Craft Brewers Conference, Nashville, TN., April 30  May 3.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Kirkpatrick, K. and Shellhammer, T.H. 2018. Hop Enzymes and the Interplay Between Beer Style and Hop Cultivar. Oral presentation at the Brewing Summit, San Diego, CA, August 12  15.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Barnette, B. and Shellhammer, T.H. 2018. Evaluating the Impact of Dissolved Oxygen on Dry-Hopped Beer Flavor and Aroma. Poster presentation at the Brewing Summit, San Diego, CA, August 12  15.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Shellhammer, T.H., 2018. Evaluating the Impact of Dissolved Oxygen on Dry-Hopped Flavor Stability in Beer. Oral presentation at the Craft Brewers Conference, Nashville, TN., April 30  May 3.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Barnette, B and Shellhammer, T.H. 2018. Quantification of Hop Acids Present in Spent Brewer's Grain. Poster presentation at the 2018 American Hop Convention/Hop Research Council Winter Meeting, Palm Desert, CA, January, 23  26.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Hahn, C. and Shellhammer, T.H. 2018. First wort hopping: an evaluation of its chemistry and sensory impact. Poster presentation at the 2018 American Hop Convention/Hop Research Council Winter Meeting, Palm Desert, CA, January, 23  26.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Kirkpatrick, K. and Shellhammer, T.H. 2018. Investigating the enzymic power of hops. Poster presentation at the 2018 American Hop Convention/Hop Research Council Winter Meeting, Palm Desert, CA, January, 23  26.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Lafontaine, S. R., Vollmer, D.M. and Shellhammer, T.H. 2018. Understanding the dry hop aroma of American hop varieties. Poster presentation at the 2018 American Hop Convention/Hop Research Council Winter Meeting, Palm Desert, CA, January, 23  26.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: 2. Shellhammer, T.H., 2018, Dry-hopping Research at OSU: A peek inside the Shellhammer Lab, Invited presentation to BJCP Judges at the HomeBrewCon, Portland, OR, June 27.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Weldon, B. 2017. Differences in Managing the Mildews: Staying out of trouble with powdery mildew and downy mildew. Cornell Hops Conference. December 2017.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Weldon, B. 2017. Cold induced disease resistance may explain unexpected stalling of foliar epidemics of hop powdery mildew (Podosphaera macularis).American Phytopathology Society. August 2017.
  • Type: Websites Status: Published Year Published: 2018 Citation: School of Integrative Plant Science: Hops. Cornell University College of Agriculture and Life Sciences. Website. https://sips.cals.cornell.edu/extension-outreach/hops/
  • Type: Websites Status: Published Year Published: 2017 Citation: Integrated Pest Management: Hops. Washington State University College of Agricultural, Human, and Natural Resource Sciences. Website. https://ipm.wsu.edu/specialty-crops/hops/
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Prera, A., R. Fortenbery, and TL Marsh. 2017. Risk Management: Potential for U.S. Microbreweries, Journal of Agribusiness, Vol 35, No2: 143-160.
  • Type: Journal Articles Status: Accepted Year Published: 2018 Citation: Gabrielyan,G., T. L. Marsh, J. McCluskey, and C. Ross. 2018. Hoppiness is Happiness? Under-fertilized Hop Treatments and Consumers Willingness to Pay for Beer, accepted Journal of Wine Economics.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Weldon, B. 2018. Early season suppression of hop powdery mildew via acute overnight cold events. American Hop Convention. January 2018. Poster.
  • Type: Conference Papers and Presentations Status: Submitted Year Published: 2018 Citation: Xi Gu, PhD student, submitted abstract to 2018 Agricultural and Applied Economics Association Meeting, Price Linkage and Volatility Spillover of Beer Inputs."
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Gu, X. and T.L. Marsh. 2018. Pesticide Substitution under Maximum Residue Limits: Application to Hops Production. Agricultural and Applied Economics Association, Chicago.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Weldon, B, L. Cadle-Davidson, D.H. Gent, S. Wolfenbarger, B.J. Knaus, N.J. Gr�nwald, and D.M. Gadoury. 2018. AmpSeq based SNP marker development for population analysis of geographically diverse isolates of hop powdery mildew (Podosphaera macularis). International Congress of Plant Pathology, August 2018. Poster.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Xiangrui Wang, Ron C. Mittelhammer, Thomas L. Marsh; Jill J. McCluskey. 2018. Divestiture of U.S. Businesses May Fail as a Merger Remedy: The Case of the U.S. Beer Industry. Agricultural and Applied Economics Association. Chicago.
  • Type: Journal Articles Status: Under Review Year Published: 2018 Citation: Lafontaine, S. R., Varnum, S., Roland, A., Delpech, S., Dagan, L., Kishimoto, T. Vollmer, D.M. and Shellhammer, T.H. (in review). Impact of harvest maturity on the aroma characteristics and chemistry of Cascade hops during dry-hopping. Journal of Food Chemistry.
  • Type: Journal Articles Status: Accepted Year Published: 2018 Citation: Lafontaine, S. R., Vollmer, D.M. and Shellhammer, T.H. (in press). Aroma extract dilution analysis of beers dry-hopped with Cascade, Chinook, and Centennial. Journal of American Society of brewing Chemists.
  • Type: Journal Articles Status: Accepted Year Published: 2018 Citation: Lafontaine, S. R. and Shellhammer, T. H. (in press). Sensory directed mixture study of beers dry-hopped with Cascade, Centennial, and Chinook. Journal of American Society of brewing Chemists.
  • Type: Journal Articles Status: Published Year Published: 2018 Citation: Lafontaine, S. R. and Shellhammer, T. H. 2018. Impact of dry-hopping rate on the sensory and analytical profiles in beer. Journal of the Institute of Brewing, https://onlinelibrary.wiley.com/doi/pdf/10.1002/jib.517
  • Type: Journal Articles Status: Published Year Published: 2018 Citation: Kirkpatrick, K.R. and Shellhammer, T.H. 2018. Evidence of Dextrin Hydrolyzing Enzymes in Cascade Hops (Humulus lupulus). Journal of Agricultural and Food Chemistry, 66 http://dx.doi.org/10.1021/acs.jafc.8b03563
  • Type: Journal Articles Status: Published Year Published: 2018 Citation: Hahn, C., Lafontaine, S.R., Pereira, C.B., and Shellhammer, T.H. 2018. Evaluation of the nonvolatile chemistry affecting the sensory bitterness intensity of highly hopped beers. Journal of Agricultural and Food Chemistry, 66 (13), pp 35053513. http://dx.doi.org/10.1021/acs.jafc.7b05784


Progress 09/01/16 to 08/31/17

Outputs
Target Audience:During this reporting period, we targeted and reached U.S. hop growers, researchers working on hop disease and insect problems, and other stakeholders in the hop and brewing industries. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Co-PIs, research assistants, and graduate students had opportunities to work together, share results and data, and engage in two-way communication with other researchers and with industry at venues including state hop commission meetings, Hop Research Council meetings, hop grower group meetings, Extension workshops, International Hop Growers Convention, International Brewers Symposium, American Society of Brewing Chemists, Hop Growers of America (and its Small Growers Council),Vermont Annual Hop Growers Conference, Craft Brewers Convention,Great Lakes Hop and Barley Convention, New York Hops Conference, and American Hop Convention. PhD student Adekunle Adassanya works closely with PI Doug Walsh at Washington State University in research on the molecular basis for acaricide resistance inTetranchyus urticaeand was the lead author on three journal publications published during this reporting period. Walsh also works with undergraduate students Mariany Ashanty Morales (who maintains and selects acaricide resistance and collectes mites for Objective 2b) and Antonio Cardenas (who helps maintain the mite colonies and assists with PCR diagnostic work). MS student Anne Iskra, BA student Lindee Elmblade, and high school student Trevor Clarkworkwith PI Dave Gent on a wide variety of tasks associated with objectives 1-4; Iskra was the lead author on a nitrogen fertility impacts journal article and made presentations on this topic to several audiences. PhD student Scott Lafontaine and MS students Kaylyn Kirkpatrick and Bradley Barnette work on both laboratory and extension outreach aspects of this project with PI Thomas Shellhammer. Shellhammer also provided mentoring to 14 undergraduate student research assistants (Dalton Behrens, Alicia Collier, Larissa Hitzman, Ryan Howe, Cameron McDaniel, Ruth Nelson, Kevin Pigao, Lorena Ramos, Ian Schacter, Quinn Schmidt, Ben Smallen, Nic Spatafora, Andrew Sutton, and Jacob Watt). PhD student William Weldon works with PIs David Gadoury and Steve Miller, focusing on hop powdery mildew distribution and race detection in the laboratory and in the field. PhD student Xi Gu works with PI Thomas Marsh on the economic aspects of the project. He conducts statistical analyses and literature reviews, presents findings at conferences, and is working on developing one or more journal articles and developing economic thresholds. How have the results been disseminated to communities of interest?Results have been disseminated via the numerous scientific journal publications and conference presentations enumerated under the "Products" section of this report. Results have also been disseminated in classroom presentations, workshops, and field days, and via online content on a variety of industry and university websites. In addition to regional and national audiences of hop end-users (brewers) and other stakeholders, presentations were made to communities of interest in Canada, England, Japan, and Slovenia. PIs with extension outreach responsibilities field hundreds of email and telephone inquiries from growers throughout the established hop-growing regions of the Pacific Northwest (Washington, Oregon, Idaho) and Great Lakes (Michigan, Minnesota, Ohio, New York) regions, but also reported inquiries from growers in Connecticut, South Carolina, Virginia, Maine, Indiana, Vermont, New Jersey, Pennsylvania, and Maryland in the project period, as well as international inquiries from Canada, Germany, Ethiopia, Italy, and the United Kingdom. Numerous inquiries have come from active and recently discharged U.S. military personnel seeking to establish a hop farm as part of a transition to civilian life. The project PIs work closely with the Hop Growers of America (providing content for their well-used industry website http://usahops.org), the hop commissions in each state and region, the Hop Research Council, and the U.S. Hop Industry Plant Protection Committee to provide timely and targeted outreach.Responses were given throughout the reporting period to hundreds of requests for information and/or advising from stakeholders. Information on germplasm reaction to multiple strains of the powdery mildew pathogen was provided to all public sector breeding programs in the Pacific Northwest and three private breeding programs. Public and private sector breeding programs are utilizing parents identified from this screen in crosses. Numerous informal discussions with breeding programs have occurred, and breeders have been encouraged to use germplasm identified as resistant through the powdery mildew screens. What do you plan to do during the next reporting period to accomplish the goals?Objective 1. Coordinate aroma sensory studies with cones from nitrogen timing study. Repeat nitrogen timing studies in Washington, analyze data, and submit manuscript(s). Repeat final year of irrigation timing study; analyze data. Objective 2a. Repeat final year of nitrogen rate studies in Oregon; analyze complete data set to formalize damage function; validate with independent data collected from commercial yards in Oregon; prepare and submit manuscript. Objective 2b. Objective 2c. Complete modeling of disease spread. Prepare and submit manuscripts describing overwintering of powdery mildew. Objective 3. Complete germplasm evaluation and preparePlant Disease Mangement Reportmanuscript for submission and distribution to industry. Objective 4. Continue to conduct outreach on emerging research results as in previous reporting periods. Synthesize results of four-year activities into final, comprehensive reports and outreach materials. Objective 5 Transdisciplinary review of transcripts from field interviews and analysis of information. Prepare manuscripts on sociological and economic impacts. Objective 6 Continue mentoring graduate and undergraduate students.

Impacts
What was accomplished under these goals? Objective 1.Nitrogen rate studies were completed in 2016 in a commercial yard of cultivar Tomahawk in Washington and experimental plots of cultivar Willamette in Oregon. In Washington, powdery mildew levels on leaves during the summer, young leaves formed late in the season, and cones were increased with increased nitrogen fertilization. InOregon, levels of the hop looper and associated defoliation from its feeding increased in proportion to nitrogen rate. Consistent effects on hop aphid and spider mites were not detected in 2016. Concurrent with studying the impacts of nutrient levels on pests, we studied impacts on hop quality components (as a pest-free hop is not worth much if it isn't a quality hop). In Washington there was a non-significant trend for reduced alpha-acids content with the highest rate of nitrogen fertilization. Total oil content of cones was slightly, yet significantly, reduced by the highest rate of nitrogen. However, cone yield was greatest with the high rate of nitrogen fertilizer, whereas yield of alpha-acids was statistically similar with the high and intermediate rates of nitrogen. Differences in sensory perception of aroma were found between cones receiving the intermediate rate of nitrogen fertilizer versus low or high rates.In Oregon, there was also a tendency for levels of alpha-acids to decrease with increasing nitrogen rate, although oil content was not affected.Cone yield and total alpha-acids yield were greatest with the higher rates of nitrogen. In both locations/cultivars, cone nitrate levels were directly related to nitrogen fertilization rate. These results indicate it may be possible to moderate powdery mildew, multiple arthropod pests, and nitrate levels in cones without negatively impacting cone yield and quality by avoiding unduly high rates of nitrogen fertilizer. However, the optimal fertilization rate for maximizing alpha-acids yields appears to be influenced by year-dependent factors that affect plant growth rate in spring. In 2017, related experiments were begun to evaluate the impact of the timing of nitrogen fertilizer applications on powdery mildew, yield, and various cone quality factors. In this study a single rate of nitrogen has been applied to all plots, but the timing of that application was varied from early, to mid, to late season. Measurements are in progress, although preliminary data indicates that the later timing of nitrogen may increase levels of powdery mildew. Assessment of cones for differences in nitrate accumulation, brewing chemistry, and aroma are planned, both by scientists involved with this project and independently by industry collaborators at Sierra Nevada Brewing Company. Experiments were continued to quantify the impact of early spring water stress on development of powdery mildew on large-scale plotsof Cascade and Zeus in Washington State. Objective 2a.Studies were initiated to determine the resiliency of biological control of spider mites to disturbances caused by excessive rates of nitrogen fertilization and use of a broad spectrum insecticide (bifenthrin). Experimental plots of cultivar Willamette were established in 2017 in a field where stable biological control of spider mites was established and damaging levels of the pest have not developed since 2008. Data collection is in progress, however, early results indicate that a single application of a broad spectrum insecticide is sufficient to perturb biological control, independent of nitrogen fertilization rate. Cones will be harvested from these plots and evaluated for damage from spider mites, and the data used to further refine a damage function that predicts when this pest will infest and damage cones. Sampling also was conducted in eight commercial hop yards to provide independent data for validation of the damage function. Objective 2b. A total of 36T. urticaepopulations were collected from conventional hop yards in the Yakima Valley of Washington. Mites were evaluated for phenotypic resistance to three major acaricides (etoxazole, spirodiclofen, fenpyroximate) and resistance genotypes to six acaricides (abamectin, bifenthrin, bifenazate, etoxazole, fenpyroximate,spirodiclofen). Many field populations exhibited multiple acaricide resistance of varying degrees. Sampled populationsharbored multiple mutations across target sites such as I1017F in chitin synthase 1 gene, G126S in cytochrome b, and M918L, F1534S and F1538I in the voltage-gated sodium channel gene, with these mutations occurring in 97, 85.7, 21, 34 and 100 % of the tested population respectively. We detected high expression of resistance-associated detoxification belonging to cytochrome P450s, glutathione S transferases, and carboxylesterases. Objective 2c.We formulated and fit a network model to describe the month-to-month spread of powdery mildew on hop among yards at the landscape (mesoscale) level. An individual hop yard was considered a node in the model, whose disease status in a given month was modeled to be a function of its disease status in the preceding month and cultivar susceptible, and disease spread from other nodes as influenced by their disease incidence, size, distance away, and wind variables. Parameter estimates for edge weights representing these variables were estimated by penalized regression. Evaluation of predicted versus actual incidence of diseased plants during 2014, 2015, and 2016 yielded coefficients of determination ranging from 0 to 0.77 during May, whereas predictions for June and July ranged from 0.51 to 0.91. Given that powdery mildew overwinters in less than 5% of hop yards in western Oregon, the network model provides a useful description of risk factors that underlie the spread of powdery mildew at the mesoscale. Objective 3.A systemic evaluation of powdery mildew reaction was continued with publically available male hop germplasm in the USDA collection. Approximately 141 individuals were screened in a sequence of controlled inoculations with multiple strains of the hop powdery mildew fungus that are prevalent in the Pacific Northwestern U.S. A set of 23 accessions were identified that were resistant to the most prevalent strains of the pathogen present in the region. These accessions are being screened for novel strains of the pathogen from Europe to characterize their resistance and determine if it is a new sourceof resistance. A referreed technical report detailing the findings is underdevelopment and will be shared with public and private sector breeding programs to accelerate introgression of resistance into new cultivars. Objective 4. See "How have the results been disseminated to communities of interest" below for details. Objective 5. Interviews were conducted with a number of Washington State growers in 2017 to develop data from a qualitative sociological standpoint. The interview guide was revised and expanded as results emerge from previous years' interviews and greater understanding is achieved regarding pest management practices and potential barriers to IPM adoption among producers. Data are beginning to emerge regarding changes in mite and disease management programs including motivation for changes, cooperation/coordination with neighboring growers, the role of research in the decision-making process. Economic research conducted in the course of this project has resulted in several publications listed under Products in this report. Objective 6. See list of students and their roles under "Opportunities for training and professional development," below.

Publications

  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Walsh, D.B. Spider Mite Control on Hops. Great Lakes Hop and Barley Convention. Detroit, MI, March 2, 2017
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Walsh, D.B. Pesticide Residues and Biological Materials Present on Hops Grown Under a Variety of Input Regimes and in Beers Brewed Under a Variety of Hopping Regimes. American Hop Convention. Bend, OR, January, 20, 2017
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Walsh, D.B. Integrated pest management of Arthropods on Hops. Progress Report 2016. Hop Research Council, Bend, OR, January 17, 2017
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Walsh, D.B. Washington Hop Growers Association. IPM on Hops. Yakima, WA, January 6, 2017
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Walsh, D., 2017. Integrated pest management of arthropods on hops: 2016. Proceedings Hop Research Council, Winter meeting. Bend, OR.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Walsh, D. 2016. IPM on Hops. Hop Research Council
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Walsh, D.B. IPM in US Hopyards. International Hop Growers Conference, Yakima, WA, August 1, 2017
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Walsh, D.B. Characterizing acaricide resistance in spider mite populations in hopyards. International Hop Growers Conference, Yakima, WA, July 31, 2017
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Walsh, D.B. Integrated pest management of Arthropods on Hops. Progress Report 2017. Hop Research Council, Corvallis, OR, July 28, 2017
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Walsh, D.B. Reducing the Impact of Industry-Critical Insect and Disease Problems in Hop through Development of Preventive and Predictive Strategies. Craft Brewers Convention. Washington, DC, April 13, 2017
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Walsh, D.B. Mite Biology and Recent Experiments on Hops. Yakima Chiefs Green Chief seminar series. Sunnyside, WA, March 23, 2017
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Walsh, D.B. Reducing the Impact of Industry-Critical Insect and Disease Problems in Hop through Development of Preventive and Predictive Strategies. Specialty Crop Committee. USDA NIFA. August 2, 2016
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Claassen, B. J., Wolfenbarger, S. N., Havill, J. S., Orshinsky, A. M., and Gent, D. H. 2017. Infestation of hop seed (Humulus lupulus) by chasmothecia of the powdery mildew fungus, Podosphaera macularis. Plant Disease 101:1323.
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Gent, D. H., Massie, S. T., Twomey, M. C., and Wolfenbarger, S. N. 2017. Adaptation to partial resistance to powdery mildew in the hop cultivar Cascade by Podosphaera macularis. Plant Disease 101:874-881.
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Wolfenbarger, S. N., Twomey, M. C., and Gent, D. H. 2017. Powdery mildew reaction of hop cultivars and USDA germplasm. Plant Disease Management Reports 11:V049.
  • Type: Conference Papers and Presentations Status: Awaiting Publication Year Published: 2017 Citation: Gent, D. H., Bhattacharyya, S., Ruiz, T., Twomey, M., and Wolfenbarger, S. 2017. A network model to predict spread and mesoscale level development of hop powdery mildew. Phytopathology
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Iskra, A. E., Lafontaine, S. R., Phillips, C., Shellhammer, T. H., Trippe, K., Twomey, M. C., Woods, J. L., and Gent, D. H. 2017. The multifaceted influence of nitrogen fertility on hops in the Pacific Northwest. Proceedings of the International Brewers Symposium on Hop Flavor and Aroma in Beer. July 25-28, Oregon State University, Corvallis, Oregon.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Gent, D. H., Bhattacharyya, S., Claassen, B. J., Grove, G. G., Nelson, M. E., Probst, C., Twomey, M., and Wolfenbarger, S. 2017. Survival, persistence, and landscape-level development of powdery mildew. Proceedings of the Scientific Commission of the International Hop Growers Convention, June 25-29, St. Stefan a. Walde, Austria.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Gent, D. H. 2017. Overwintering biology of the hop powdery mildew fungus: from focal infections to landscape-level spread. Winter Meeting of the Hop Research Council. January 18, Bend, OR.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Iskra, A. E., and Gent, D. H. 2017. The multifaceted impact of nitrogen fertilization. Winter Meeting of the Hop Research Council. January 18, Bend, OR.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Wolfenbarger, S. N., and Gent, D. H. 2017. Cascade and powdery mildew: why, where, and whats next. Winter Meeting of the Hop Research Council. January 18, Bend, OR.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Gent, D. H. 2017. Overwintering biology of the hop powdery mildew fungus. Annual Report of the Hop Research Council, Hubbard, Oregon.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Gent, D. H. 2017. 20 years of powdery mildew in the Pacific Northwest: what a long strange trip its been. International Hop Growers Convention. 31 July, Yakima, Washington.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Gent, D. H. 2017. Revisiting downy mildew management and fungicide resistance. Yakima Chief-Hop Union. March 23, Kaizer, Oregon.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Gent, D. H. 2017. Best management practices for priority diseases and pests. Vermont Annual Hop Growers Conference, 25 February, Burlington, VT.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Gent, D. H. 2017. Winter and spring die out of hops: possible causes and considerations. D and M Chem Grower Meeting. February 3, Yakima, WA.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Gent, D. H. 2017. Mildew update and outlook for 2017. Wilbur Ellis grower meeting. February 2, Woodburn, OR.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Gent, D. H. 2017. The 2016 powdery mildew experience. GS Long Grower Meeting. January 11, Yakima, WA.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Iskra, A. E., and Gent, D. H. 2017. Nitrogen fertility: influences on pests, mildew, and cone quality factors of concern to brewers. GS Long Grower Meeting. January 11, Yakima, WA.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Gent, D. H. 2017. From flag shoots to landscape-level development of powdery mildew. Washington Hop Industry Annual Meeting, 6 January, Yakima, WA.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Iskra, A. E., and Gent, D. H. 2017. Nitrogen fertility: influences on pests, mildew, and cone quality factors of concern to brewers. Washington Hop Industry Annual Meeting, 6 January, Yakima, WA.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Wolfenbarger, S. N., and Gent, D. H. 2017. What we know (and don't) about powdery mildew on Cascade. Washington Hop Industry Annual Meeting, 6 January, Yakima, WA.
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Sharp, D., Vollmer, D., Qian, Y.P., and Shellhammer, T.H. 2017. Examination of glycoside hydrolysis methods for the determination of terpenyl glycosides contents of different hop cultivars. Journal of the American Society of Brewing Chemists. 75(2) 101-108.
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Sharp, D., Steensels, J., Shellhammer, T.H. 2017. The effect of hopping regime, cultivar and ?-glucosidase activity on monoterpene alcohol concentrations in wort and beer. Journal of the Institute of Brewing. 123: 185-191.
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Vollmer, D.M., Algazzali, V. and Shellhammer, T.H. 2017. Aroma Properties of Lager Beer Dry-Hopped with Oxidized Hops. Journal of the American Society of Brewing Chemists. Journal of the American Society of Brewing Chemists. 75(1) 22-26.
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Sharp, D., Qian, Y.P., Clawson, J.C. and Shellhammer, T.H. 2017. Comparison of the contributions of hop pellets, super critical fluid hop extracts, and extracted hop material to the hop aroma and terpenoid content of kettle hopped lager beers. MBAA Technical Quarterly. 54(1), 2-10.
  • Type: Journal Articles Status: Published Year Published: 2016 Citation: Sharp, D., Qian, Y.P., Clawson, J.C. and Shellhammer, T.H. 2016. An exploratory study toward describing hop aroma in beer made with American and European Hop Cultivars. BrewingScience. Nov/Dec Vol 69, 112-122.
  • Type: Journal Articles Status: Published Year Published: 2016 Citation: Vollmer, D. and Shellhammer, T.H. 2016. Influence of hop oil content and composition on hop aroma intensity in dry-hopped beer. Journal of the American Society of Brewing Chemists. 74(4), 242-249.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Shellhammer, T.H. 2017. Controlling dry-hop flavor in beer. Oral presentation at the 2nd International Brewers Symposium on Hop Aroma and Flavor in Beer, Corvallis, OR, July 25  28.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Barnette, B and Shellhammer, T.H. 2017. Quantification of Hop Acids Present in Spent Brewer's Grain. Poster presentation at the 2nd International Brewers Symposium on Hop Aroma and Flavor in Beer, Corvallis, OR, July 25  28.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Hahn, C. and Shellhammer, T.H. 2017. First wort hopping: an evaluation of its chemistry and sensory impact. Poster presentation at the 2nd International Brewers Symposium on Hop Aroma and Flavor in Beer, Corvallis, OR, July 25  28.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Kirkpatrick, K. and Shellhammer, T.H. 2017. Investigating the enzymic power of hops. Poster presentation at the 2nd International Brewers Symposium on Hop Aroma and Flavor in Beer, Corvallis, OR, July 25  28.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Lafontaine, S. R., Vollmer, D.M. and Shellhammer, T.H. 2017. Understanding the dry hop aroma of American hop varieties. Poster presentation at the 2nd International Brewers Symposium on Hop Aroma and Flavor in Beer, Corvallis, OR, July 25  28.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Vollmer, D.M. and Shellhammer, T.H. 2017. Dry hopping on a small scale  considerations for achieving reproducibility. Poster presentation at the 2nd International Brewers Symposium on Hop Aroma and Flavor in Beer, Corvallis, OR, July 25  28.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Lafontaine, S. R. and Shellhammer, T.H. 2017. Evaluating hop chemistry and its contribution to hop aroma intensity in dry-hopped beer. Oral presentation (4) at the American Society of Brewing Chemists Annual Meeting, Fort Myers, FL, June 4  7.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Shellhammer, T.H. and Lafontaine, S. R. 2017. Sensory directed mixture study of beers dry-hopped with Cascade, Centennial, and Chinook. Oral presentation (31) at the American Society of Brewing Chemists Annual Meeting, Fort Myers, FL, June 4  7.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Shellhammer, T.H. 2017. Executing and Understanding Sensory Thresholds in Beer. Workshop and lecture delivered at the American Society of Brewing Chemists Annual Meeting, Fort Myers, FL, June 4  7.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Hahn, C. and Shellhammer, T.H. 2017. First wort hopping: an evaluation of its chemistry and sensory impact. Poster presentation (33) at the American Society of Brewing Chemists Annual Meeting, Fort Myers, FL, June 4  7.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Kirkpatrick, K. and Shellhammer, T.H. 2017. Investigating the enzymic power of hops. Poster presentation (35) at the American Society of Brewing Chemists Annual Meeting, Fort Myers, FL, June 4  7.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Gent, D. H. 2016. Survival and landscape-level spread of powdery mildew. Oregon Hop Commission, November 17, Mt. Angel, OR.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Gent, D. H. 2016. Hop pest management: an overview of the primary constraints for Pacific Northwest producers. Home and Commercial Agriculture Extension Workshop, August 13, Bend, OR.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Gent, D. H. 2016. Cultural practices and hop production: a primer. Home and Commercial Agriculture Extension Workshop, August 13, Bend, OR.
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Peltz, M. and Shellhammer, T.H. 2017. Ethanol content has little effect on the sensory orthonasal detection thresholds of hop compounds in beer. Journal of the American Society of Brewing Chemists. 75(3) 221-227
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Sharp, D., Qian, Y.P., Shellhammer, G.M., and Shellhammer, T.H. 2017. Contributions of select hopping regimes to the terpenoid content and hop aroma profile of ale and lager beers. Journal of the American Society of Brewing Chemists. 75(2) 93-100.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Barnette, B and Shellhammer, T.H. 2017. Quantification of Hop Acids Present in Spent Brewer's Grain. Poster presentation (59) at the American Society of Brewing Chemists Annual Meeting, Fort Myers, FL, June 4  7.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Lafontaine, S., and Shellhammer, T.H. 2017. Understanding the impact hopping rate has on the aroma quality and intensity of dry hopped beers. Oral presentation #18 at the 36th Congress of the European Brewing Convention, Ljubljana, Slovenia, May 14 - 18.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Lafontaine, S., Hahn, C. and Shellhammer, T.H. 2017. Insight into the American IPA. A deconstruction of Americas popular beer style. Poster presentation #082 at the 36th Congress of the European Brewing Convention, Ljubljana, Slovenia, May 14 - 18.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Perkins, J, Bodah, Z. and Shellhammer, T.H., 2017. Unintended over-attenuation from dry-hopping beers: A presentation of brewery and academic research. Oral presentation at the Craft Brewers Conference, Washington D.C., April 10  13.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Shellhammer, T.H., 2017. Brewers Association Research Update: Sensory Directed Mixture Study of Beers Dry-Hopped with Cascade, Centennial, and Chinook. Oral presentation at the Craft Brewers Conference, Washington D.C., April 10  13.
  • Type: Other Status: Published Year Published: 2016 Citation: Shellhammer, T.H., Lafontaine, S.R., Vollmer, D., and Pereira, C. 2016. Identifying brewing qualities which aid hop breeding: Examining hop oil content and its influence on dry-hop aroma in beer. Technical report to the Hop Research Council. 28 pages.
  • Type: Other Status: Published Year Published: 2017 Citation: Shellhammer, T.H., 2017, Recent Advances in Hops Aroma, Chemistry and Processing, Invited presentation to the ABInbev Global Brewmaster Program, St. Louis, MO, April 4.
  • Type: Other Status: Published Year Published: 2016 Citation: Sharp, D. and Shellhammer, T.H. 2016. Modeling Hop Aroma: Effect of hopping regime, cultivar and yeast. Oral presentation at the Inbev Baillet Latour Foundation Annual Scientific meeting, Leuven, Belgium, November 30.
  • Type: Other Status: Published Year Published: 2016 Citation: Shellhammer, T.H., 2016, The transformative effect craft beer is having on the brewing industry, Invited presentation to the Suntory World Research Center scientific staff, Kyoto, Japan, November 16.
  • Type: Other Status: Published Year Published: 2016 Citation: Shellhammer, T.H., 2016, The role of hop-derived glycosides and oxidized hop acids in beer flavor, Invited presentation to the Suntory World Research Center brewing research and development team, Kyoto, Japan, November 16.
  • Type: Journal Articles Status: Accepted Year Published: 2017 Citation: Prera, A., R. Fortenbery, and TL Marsh. 2017. Risk Management: Potential for U.S. Microbreweries, accepted Journal of Agribusiness.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Hahn, C., Lafontaine, S. R. and Shellhammer, T.H. 2017. A comprehensive evaluation of the nonvolatile chemistry affecting the bitterness intensity of highly hopped beers. Oral presentation (18) at the American Society of Brewing Chemists Annual Meeting, Fort Myers, FL, June 4  7.
  • Type: Other Status: Published Year Published: 2016 Citation: Marsh, T.L, Interviewed for From farm to glass: How hops are priced, National Public Radio, 12/26/2016.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Gu, X. and T.L. Marsh. 2017. Pesticide Substitution under Maximum Residue Limits: Application to Hops Production, Agricultural and Applied Economics Association, Selected Paper, Chicago.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Xiangrui Wang, Ron C. Mittelhammer, Thomas L. Marsh, Jill J. McCluske. 2017, Divestiture of U.S. Businesses May Fail as a Merger Remedy: The Case of the U.S. Beer Industry, Agricultural and Applied Economics Association, Selected Paper, Chicago.
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Adesanya, A.W., M.A. Morales, D.B. Walsh, L.C. Lavine, M.D. Lavine, & F. Zhu, 2017. Mechanisms of resistance to three mite growth inhibitors of Tetranychus urticae in hops. Bulletin of Entomological Research, https://doi:10.1017/S0007485317000414
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Nakawuka, P., R.T. Peters, S. Kenny, and D. Walsh. 2017. Effect of deficit irrigation on yield quantity and quality, water productivity, and economic returns for four cultivars of hops in the Yakima Valley, Washington State. Industrial Crops and Products. 98(2017) 82-92
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Adesanya, A., M. Morales, D. Walsh, L. Lavine, & F. Zhu. Multiple acaricide resistance of Teteranchyus urticae in hops. Pacific Branch Entomological Society of America. Portland, OR, April 2017
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Adesanya, A., M. Wu, D. Walsh, L. Lavine, & F. Zhu. Evaluating the role of NADPH-cytochrome P450 reductase in acaricide resistance in the generalist herbivore: Tetranchyus urticae Koch. Entomological Society of America. Portland, OR, April 2017
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Adesanya A.W.#, F. Zhu, D.B. Walsh & L.C. Lavine. Mechanisms of resistance to mite growth regulators in the two-spotted spider mite, Teteranchyus urticae. XXV International Congress of Entomology, Orlando, FL, September 2016
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Morales M.A., A.W. Adesanya#, B.M. Mendoza, C. Nguyen, L.C. Lavine, D.B. Walsh and F. Zhu. Precise molecular diagnostics for miticide resistance in Tetranychus urticae on hops. XXV International Congress of Entomology, Orlando, FL, September 2016


Progress 09/01/15 to 08/31/16

Outputs
Target Audience:Our primary audiences are U.S. hop growers, researchers working on hop disease and insect problems, and other stakeholders in the hop industry. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?The New York Hops Conference provided breakout sessions for both new and experienced hop growers and end users. Presentations at plant pathology and entomology conferences (detailed under Products) provided information exchange with other researchers. Students working directly on this project include: Anne Iskra, MS student research assistant and intern, USDA-ARS / Oregon State University; Lindee Elmblade, BA candidate and research assistant, Oregon State University; William Weldon, PhD student and research lead for Cornell University; Alicia Collier,BS candidate and research assistant, Oregon State University; Ryan Howe,BS candidate and research assistant, Oregon State University; Joshua McCallum,BS candidate and research assistant, Oregon State University; Cameron McDaniel,BS candidate and research assistant, Oregon State University; Ruth Nelson,BS candidate and research assistant, Oregon State University; Kevin Pigao,BS candidate and research assistant, Oregon State University;Andrew Sutton,BS candidate and research assistant, Oregon State University; Jacob Watt,BS candidate and research assistant, Oregon State University; Ziran Wang,BS candidate and research assistant, Oregon State University; Scott Lafontaine, lead research assistant and PhD canditate, Oregon State University; Kaylyn Kirkpatrick, research assistant and MS candidate, Oregon State University; Bradley Barnette, research assistant and MS candidate, Oregon State University; Xi Gu, PhD candidate and economics researcher, Washington State University;Adekunle Adesanya, PhD candidate and entomology researcher, Washington State University. How have the results been disseminated to communities of interest?Co-PIs and their graduate studentsmade conference and meeting presentations in Washington, Oregon, Idaho, Florida, New York, Michigan, Pennsylvania, Vermont, Indiana, and Maryland.The 2015 New York Hops Conference was held over 2 days and reached over 350 participants in our target audience.Meetings with the Washington and Oregon hop commissions (2 with each during the reporting period), and the Great Lakes and New England hop grower associations. National presentations at the Craft Brewers Association, World Browing Congress,and American Hop Convention. Presentations at the American Phytopathological Society and Entomological Society of America. International audience presentations at the Institute of Brewing and Distilling Examiners (London, England), Brewing Convention of Japan (Tokyo), and Chinese Brewing Congress (Jinan).Dozens of formal and informaltalks to grower groups. Presence on social media. Preliminary results of our researchhave been pushed to friends of the Northwest Hop Information Network Facebook page when appropriate. Information on germplasm reaction to multiple strains of the powdery mildew pathogen was provided to all public sector breeding programs in the Pacific Northwest and three private breeding programs. Numerous informal discussions with breeding programs have occurred, and breeders have been encouraged to use germplasm identified as resistant through the powdery mildew screens. At least three breeding programs have or expressed they will make crosses with resistant materials identified herein. What do you plan to do during the next reporting period to accomplish the goals?Continue outreach to growers in the Pacific Northwest, Great Lakes Region, and Eastern U.S. Presentations at all of the aformentioned venues. Further data collection is underway on Objectives 1, 2, and 3, as scheduled in our proposal timeline. Approximately half of the research hop yard at the New York State Agricultural Experiment Station is being replanted with a more mildew-susceptible cultivar (Zeus), which should increase our ability to create epidemics needed for our study.The irrigation and nitrate fertilization studies summarized under "What was accomplished" (Objective 2)will be repeated in 2017 in both cv. Cascade and Zeus to verify the results obtained in 2016, further refine when the first irrigation should be made to avoid yield damage, and validate the results on a later trained and harvested cultivar.

Impacts
What was accomplished under these goals? Objective 1:Nitrogen rate studies were initiated in a commercial yard of cultivar Tomahawk in Washington and in experimental plots of cultivar Willamette in Oregon to determine how nitrogen fertilization rate influences powdery mildew on hop, as well as arthropod pests, yield, and nitrate accumulation in cones. In the commercial yard, the incidence of leaves and cones with powdery mildew in plots that received 90 to 270 kg nitrogen per hectare was increased late in the season with the highest fertilization rate.In Oregon, the abundance of hop looper and defoliation from its feeding increased proportionally with increasing nitrogen fertilization. Sensory evaluations were conducted on cones from both experiments.In the 2015 studies, in both cultivars there was weak evidence that raters were able to differentiate cones that received the highest and low rates of nitrogen.This was not consistent in 2016 though, indicating that nitrogen fertilization has only a small or inconsistent impact on aroma.Following the 2015 harvest, hop cones with the lowest and highest levels of nitrate were utilized in pilot-scale brewing studies to quantify fate and transfer of nitrate through the brewing process with the goal to provide brewers with a simple calculator to predict nitrate levels in their finished product based on nitrate levels in the raw ingredients and hopping rate.Additionally, experiments were initiated to quantify the impact of early spring water stress on development of powdery mildew.Large-scale plots were established in a commercial yard of Cascade in Washington State to test a broad range of industry practices for timing the first irrigation of the season.There was a trend for less powdery mildew on leaves and cones where irrigation was delayed, although these differences were not statistically significant.Cone yield was reduced 15% when the first irrigation was delayed until 27 May as compared to 4 May.Other measures of cone quality were unaffected by the irrigation treatments. The Shellhammer fermentation science lab provided the chemistry, sensory and quality evaluations on hops and beer. Chemical attributes such as hop acids, oil content and oil composition were analyzed and compared. Although some minor trends exist, in general the variation of nitrogen treatments had minimal impact on the chemical attributesthat are important to brewing quality.Sensory discrimination testing was performed on the aroma of the dry hop cones from the Willamette and CTZ treatment groups. Triangle tests were used to assess whether the aromas of the hop cones between the high, medium, and low treatment groups were different. In brief, no differences were detected in the aromas between the different CTZ and Willamette treatment groups.Hop cones from the low and high CTZ treatment groups were used to hop beer on the pilot scale (~3hL). A wort made with 100% two row malt was kettle hopped (target 40 BU), whirlpool hopped (5 g/L) and dry-hopped (4 g/L) with hop cones from the low and high treatment groups. Sensory discrimination testing (triangle tests, 40 panelists) showed that the beers made with the high and low treatment groups were significantly different (p < 0.00001). The high nitrogen treatment beer had less bitterness and less of an herbal, skunky, compost aroma. The low nitrogen treatment had a harsher flavor, was more bitter and less pleasant to drink. The fate of nitrate was assessed throughout the production of these beers and the analysis of the beer is still ongoing. We arealso investigating the role of input factors in hops (e.g. oil composition, oil content, location, farm, kilning regime, etc.) and how they relate to beer aroma performance in dry-hopped beer. Sensory descriptive analysis is being used to scale quality attributes (i.e. citrus, herbal, etc.) on beers produced on the pilot scale (~40 L) by dry hopping the same pale malt base beer with different lots of the same cultivar. The chemical composition of the oil for these hops has been analyzed using steam distillation and GC/MS. Sixty unique lots of Cascade have been dry hopped and analyzed. To predict the aroma performance of the Cascade treatments mathematical modeling is currently underway to relate the chemical composition of the hop oil to the descriptive analysis sensory responses. Chinook and Centennial are also being investigated to see if the model developed for Cascade aroma performance will predict aroma performance of these varieties. Twelve unique lots of each of these cultivars have been dry hopped on the pilot scale (~40L) and descriptive analysis is currently being performed. Objective 2:Analysis was conducted on 11 years of historical data collected from experimental plots in Oregon to identify risk factors associated with spider mite damage to cones, and predict when cone damage is most likely to occur. Present analyses indicate that the best predictor of cone damage is cumulative mite-days in the upper canopy after bloom. Determinants of this variable were absence of spider mites in early spring, and lack of natural enemies in early and late spring. This finding indicates that early season management of spider mites may not be essential when biological control is active, and may even predispose yards to later outbreaks of spider mites when cone damage is most likely to occur. Further data collection is in progress.Historical data from 399 commercial hop yards collected during 2000 to 2016 was analyzed to identify risk factors linked to flag shoot occurrence and frequency. Analyses indicated that prior occurrence of flag shoots, disease levels in the previous season, pruning method, and winter temperature were associated with flag shoot development. Extensive surveys of hop yards in Oregon during 2014 to 2016 identified that landscape-level outbreaks of powdery mildew were associated with survival of the fungus in a small number of hop yards. In many instances, perennation of the pathogen was associated with chronic infection of highly susceptible cultivars when specific pruning practices were utilized in spring. A new collaboration with epidemiologists and statisticians to develop a network model to characterize disease spread amongst fields was developed with data from 2014 and 2015; validation with 2016 data is underway. The model may enable prediction of disease levels due to pathogen spread, providing the foundation of an area-wide IPM system for the disease in regions were overwintering levels of the pathogen are limiting to epidemic development. Objective 3: Substantive progress was made during this project reporting period on cultivar susceptibility to downy mildew. Associations with chemical characteristics and region of origins have been made and results to date presented in an article published in Plant Health Progress.A systemic evaluation of powdery mildew reaction was conducted with publically available male hop germplasm in the USDA collection. Approximately 141 individuals were screened in a sequence of controlled inoculations with multiple strains of the hop powdery mildew fungus that are prevalent in the Pacific Northwestern U.S. A referred technical report detailing the findings is in development and will be shared with public and private sector breeding programs to accelerate introgression of resistance into new cultivars. Objective 4: See "How have results been disseminated," second item following. Objective 5: The survey of New York hop growers provides a snapshot of current acreage and practices and will be foundational for assessing changes in knowledge and production practices in this emerging production region.Planning for economic and sociological studies was conducted, including obtaining IRB approval and training for work with human subjects. A draft interview guide was developed and grower interviews were conducted during summer 2016. Objective 6: Students mentored are listed in the section following.

Publications

  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Matthews, P. 2015. Certified planting stock from the National Clean Plant Laboratory. New York State Hops Conference. December 2015.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Sirrine, JR. 2015. Hop culture in the Great Lakes region and beyond. New York State Hops Conference. December 2015.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Gadoury, D. 2015. Powdery mildew management in hop. New York State Hops Conference. December 2015.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Miller, S. 2015. Research update and best practices in hops. Michigan Fruit and Vegetable Conference. December 2015.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Miller, S. 2016. Research update and half-day hop session. New York State Empire Expo. Syracuse, NY. January 2016.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Miller, S. 2016. Hop research update and best practices. Pennsylvania Fruit and Vegetable Growers Conference. February 2016.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Miller, S. 2016. Hop Preventive and Predictive Strategies: Research Update. Vermont Hop Conference. February 2016.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Miller, S. 2016. Hop workshop. Cornell Cooperative Extension. Ontario County, New York. March 2016.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Miller, S. 2016. Hop workshop. Cornell Cooperative Extension. Herkimer County, New York. March 2016.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Miller, S. 2016. Hop best practices and research update. Cornell Cooperative Extension. Madison County, New York. March 2016.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Miller, S. 2015. Hop Growing and Processing in the Northeast United States. Master Brewers Association of the Americas annual conference. Jacksonville, FL. Oct. 8-10.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Miller, S. 2015. Research Summary. NYS Soil and Water. Geneva, NY.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Miller, S. 2016. Hop research update. Cornell Cooperative Extension Beverage Conference. Seneca County, New York. April 2016.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Miller, S. 2016. Hops research update and best practices. Maryland Hops Conference. April 2016.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Miller, S. 2016. Hops workshop. Cornell Cooperative Extension. Franklin County, New York. May 2016.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Miller, S. 2016. Hops workshop. Cornell Cooperative Extension. Jefferson County, New York. May 2016.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Miller, S. 2016. Preventive and Predictive Strategies in U.S. Hop Pest Management. SAVOR National Food & Beverage Conference. Washington, DC. June 2016.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Miller, S. 2016. Research update: Hops. Geneva Experiment Station, Cornell University. June 2016.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Miller, S. 2016. Hops: State of the Industry. Brewery Ommegang, Cooperstown NY. August 2016.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Miller, S. Research update and best management practices in hops. Empire Farm Days. Seneca Falls, NY. August 2016.
  • Type: Websites Status: Published Year Published: 2015 Citation: Northeast Hop Alliance website. 2015. Monthly newsletter and content updates. http://northeasthopalliance.org.
  • Type: Journal Articles Status: Published Year Published: 2016 Citation: Wolfenbarger, SN, Quesada-Ocampo, LM, and Gent, DH. 2016. Powdery mildew caused by Podosphaera macular on hop (Humulus lupus L.) in North Carolina. Plant Disease 100:1245.
  • Type: Journal Articles Status: Published Year Published: 2016 Citation: Woods, JL and Gent DH. 2016. Susceptibility of hop cultivars to downy mildew: associations with chemical characteristics and region of origin. Plant Health Progress 17:42-48.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Iskra, A. I., Lafontaine, S., Phillips, C., Shellhammer, T., Trippe, K., Twomey, M., Woods, J., and Gent, D. 2016. Nitrogen fertilization increases powdery mildew, arthropod pests, and nitrate accumulation in hops. APS Pacific Division Meeting, June 28-30, La Conner, WA.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Wolfenbarger, S. N., Grove, G. G., Nelson, M. E., Ocamb, C. M., Probst, C., Twomey, M. C., and Gent, D. H. 2016. Adaptation to qualitative and quantitative host resistance by Podosphaera macularis in the Pacific Northwest. APS Pacific Division Meeting, June 28-30, La Conner, WA.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: 3. Iskra, A. E., Lafontaine, S. R., Phillips, C., Shellhammer, T. H., Trippe, K., Twomey, M. C., Woods, J. L., and Gent, D. H. 2016. Influence of nitrogen fertilization in hops on nitrate accumulation in cones, pest outbreaks, and crop yield and quality. Young Scientist Symposium, April 21-23, Chico, CA.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Gent, DH. 2016 Overwintering biology of the hop powdery mildew fungus. Annual Report of the Hop Research Council, Hubbard, Oregon.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Walsh, DB. 2016. Predictive and preventive strategies in arthropod management in hop. Annual Report of the Hop Research Council, Hubbard, Oregon.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Gent, D. H. 2016. Overwintering biology of the hop powdery mildew fungus. Summer Meeting of the Hop Research Council. July 27, Boise, ID.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Walsh, D.B. 2016. Update on arthropod IPM in PNW hops. Summer Meeting of the Hop Research Council. July 27, Boise, ID.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Gent, D. H. 2016. Downy mildew: identification, lifecycle, and management. Small Farm Conference, March 3, Danville, IN.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Gent, D. H. 2016. Downy mildew survival, spread, and control. Oregon Hop Commission, February 18, Aurora, OR.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Iskra, A. E., and Gent, D. H. 2016. Preliminary data on nitrogen fertility, pest outbreaks, and nitrate accumulation in cones. Oregon Hop Commission, February 18, Aurora, OR.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Wolfenbarger, S. N., and Gent, D. H. 2016. Susceptibility and development of powdery mildew on the cultivar Cascade. Oregon Hop Commission, February 18, Aurora, OR.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Twomey, M., and Gent, D. H. 2016. Overwintering of the powdery mildew fungus: implications for area-wide epidemic development and management. Oregon Hop Commission, February 18, Aurora, OR.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Woods, J. L., and Gent, D. H. 2016. Risk factors and prediction of mite damage to hop cones. Oregon Hop Commission, February 18, Aurora, OR.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Walsh, D.B. 2016. Preliminary data on mite and aphid management predictive and preventive strategies. Winter Meeting of the Hop Research Council. January 20, Palm Desert, CA.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Gent, D. H. 2016. Susceptibility and development of powdery mildew on the cultivar Cascade. Winter Meeting of the Hop Research Council. January 20, Palm Desert, CA.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Twomey, M., and Gent, D. H. 2016. Overwintering of the powdery mildew fungus: implications for area-wide epidemic development and management. Winter Meeting of the Hop Research Council. January 20, Palm Desert, CA.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Walsh, D.B. 2016. Preliminary data on mite and aphid management predictive and preventive strategies. Washington Hop Industry Annual Meeting. January 8, Yakima, WA.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Iskra, A. E., and Gent, D. H. 2016. Preliminary data on nitrogen fertility, pest outbreaks, and nitrate accumulation in cones. Washington Hop Industry Annual Meeting. January 8, Yakima, WA.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Wolfenbarger, S. N., and Gent, D. H. 2016. Susceptibility and development of powdery mildew on the cultivar Cascade. Washington Hop Industry Annual Meeting. January 8, Yakima, WA.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Twomey, M., and Gent, D. H. 2016. Overwintering of the powdery mildew fungus: implications for area-wide epidemic development and management. Washington Hop Industry Annual Meeting. January 8, Yakima, WA.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Woods, J. L., and Gent, D. H. 2016. Risk factors and prediction of mite damage to hop cones. Washington Hop Industry Annual Meeting. January 8, Yakima, WA.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Barbour, JD. 2016. Pest Management Studies: Miticide Rotation, Prionus mating disruption, and black vine weevil trials. Hop Research Council Summer Meeting, August 2016.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Gent, D. H. 2016. Preliminary data on nitrogen fertility, pest outbreaks, and nitrate accumulation in cones. Winter Meeting of the Hop Research Council. January 20, Palm Desert, CA.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Gadoury, D.M. 2016. Research update: powdery mildew. New York Horticultural Expo. January 2016.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Riga, MA, Weldon, W, Cadle-Davidson, L, and D Gadoury. 2016. "Shocking Effects" of Acute Cold Events in the Suppression of Hop Powdery Mildew. American Phytopathological Society.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Alex Prera, Randy Fortenbery, Thomas L. Marsh. 2016. Risk Management: Hedging Potential for U.S. Breweries, NCCC-134 selected presentation.
  • Type: Journal Articles Status: Other Year Published: 2016 Citation: Xiangrui Wang, Ron C. Mittelhammer, Thomas L. Marsh and Jill McCluskey. 2016. Divestiture of US Business May Fail as Merger Remedy: A Case Study from US Beer Industry, working paper, Washington State University.
  • Type: Journal Articles Status: Under Review Year Published: 2016 Citation: Alex Prera, Randy Fortenbery, Thomas L. Marsh. 2016. Risk Management: Hedging Potential for U.S. Breweries, under revision, Journal of Agribusiness
  • Type: Journal Articles Status: Other Year Published: 2016 Citation: Xi Gu and Marsh, Thomas L. 2016. The Interaction of Restricted and Unrestricted Chemical Usages In Hops Production under Risk and Uncertainty, working paper, Washington State University
  • Type: Journal Articles Status: Under Review Year Published: 2016 Citation: Nakawuka, P., T. Peters, S. Kenny, & D. Walsh. 2016. Effect of deficit irrigation on yield, water use efficiency and economic returns of four different cultivars of hops in the Yakima Valley, Washington State. Am. J. Plant Sci.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Volume, D. and Shellhammer, T.H. 2016. The influence of hop oil content and composition on hop aroma intensity in dry-hopped beer. Oral presentation #35 at the World Brewing Congress, Denver, CO. August 13-17.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Lafontaine, S., Wietstock, P. and Shellhammer, T.H. 2016. Update: Solid Phase Extraction of Isomerized Alpha Acids in Beer and Subsequent Spectrophotometric Measurement. Poster presentation #85 at the World Brewing Congress, Denver, CO. August 13-17.
  • Type: Other Status: Published Year Published: 2015 Citation: Walsh, DB and D Groenendale. 2014. GLP Magnitude of Residue Trial for Metaldehyde in Hop. Interregional Research Project 4, Rutgers, NJ.
  • Type: Other Status: Published Year Published: 2015 Citation: Walsh, DB and D Groenendale. 2014. GLP Magnitude of Residue Trial for Indaziflam in Hop. Interregional Research Project 4, Rutgers, NJ.
  • Type: Journal Articles Status: Published Year Published: 2016 Citation: Walsh, D.B., S.D. ONeal, A.E. George, D.P. Groenendale, R.E. Henderson, G.M. Groenendale, & M.J. Hengel. 2016. Evaluation of Pesticide Residues from Conventional, Organic, and Non-treated Hops on Conventionally Hopped, Late-Hopped and Wet-Hopped Beers. Journal of the Association of Brewing Chemists. http://dx.doi.org/10.1094/ASBCJ-2016-1115-02
  • Type: Journal Articles Status: Published Year Published: 2016 Citation: Piraneo, T. G., F. Zhu, J. Bull, M. D. Morales, L. C. Lavine, & D. B. Walsh. 2015. Mechanisms of Tetranychus urticae chemical adaptation in Pacific Northwest hops field. Scientific Reports. 5:1-12
  • Type: Books Status: Published Year Published: 2016 Citation: O'Neal, SD, DB Walsh, and DH Gent, eds. 2015. Field Guide for Integrated Pest Management in Hops. 3d ed. Pullman, WA: US Hop Industry Plant Protection Committee. 106 pp.
  • Type: Journal Articles Status: Published Year Published: 2016 Citation: Vollmer, D. and Shellhammer, T.H. 2016. Dry hopping on a small scale: considerations for achieving reproducibility. MBAA Technical Quarterly. 543(3) 140 - 144.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Gadoury, D.M. 2016. Research update: powdery mildew. New York Natural and Organic Farmers Association. February 2016.


Progress 09/01/14 to 08/31/15

Outputs
Target Audience:Hop growers, researchers working on hop insect and disease problems, and other stakeholders in the hop industry. Changes/Problems:Midway through our first year of this four-year project, our Research Plant Physiologist Stephen M. Griffith, of the USDA-ARS Research Unit in Corvallis, Oregon, retired. He was a Key Person but not a Co-PI, and would have beenresponsible for laboratory analysis. As a result of his unanticipated departure, we are contracting out to a private analytical lab for these services, at a higher cost to the project. What opportunities for training and professional development has the project provided?Students working on this project includeAnne Iskra (undergraduate research assistant and intern, BS) andLindee Elmblade (undergraduate research assistant, BA) of OSU; William Weldon (graduate research assistant, PhD) of Cornell; and Mariany Shanty Morales (undergraduate student, BS) and Adekunle Adesanya (graduate research assistant, PhD) of WSU. Opportunities for training of our target audience include each of several conferences and meetings, the presentations for which are detailed in the Projects section of this report. These events also provided opportunities for professional development amongst the scientists and students attending. Activities not reported elsewhere include: 1) Weldon attending American Phytopathological Society meetingin California and spending a week in Co-PI Dave Gent's laboratory in Oregon; 2) Morales maintaining and selecting acaracide resistance for bifenthrin, abamectin, and bifenazate; collecting mites for RNA extraction; housekeeping gene selection and RNAseq; 3) Adesanya collecting field populations of twospotted spider mite and is selecting forresistance to the three acaricides. Project Co-PIs Gadoury, Miller, and Gent were involved in the assessment of an outbreak of powdery mildew at a New York hop yard putatively on the cultivar Nugget. Subsequent testing of isolates collected in this planting by the Gent lab at OSU indicated a lack of pathogenicity on Nugget, which raised the possibility that the varietyhad been misidentified. Moderately severe powdery mildew was also assessed on Cascade in the same planting, thus raising concerns not only for the importation of races virulent on R6-based resistance, but also upon Cascade. Hops in this planting were sourced from a nursery operation in Michigan, and regulatory agencies in both NY and MI, as well as the departments of plant pathology at Cornell and MSU, along with the Gent lab at OSU are involved in monitoring the situation. How have the results been disseminated to communities of interest?A Pest Managment Strategic Plan (PMSP) was developed and produced for the U.S. hop industry during this project reporting year. Building on a foundational PMSP document produced for the Pacific Northwest states of Washington, Oregon, and Idaho in 2008, a work group was formed including growers, researchers, and other stakeholders from WA, OR, ID, the Great Lakes region, and the eastern U.S. This group met for one full day in Yakima, WA in November 2014 and the document, which received review, contributions, and editing from the work group before, during, and after the meeting, was released in January 2015. In it, pest management needs were detailed and prioritized for the U.S. hop industry. During this project reporting year, in part due to its being identified during the PMSP process, a major revision to the Field Guide for Integrated Pest Management in Hops was undertaken. The first and second editions of this handbook were released in 2009 and 2010, respectively, and addressed hop IPM in the Pacific Northwest. The expanded third edition was nearing completion as this reporting period closed, and is expected to be released during the next reporting period. The groundwork was laid for the 4th Bienniel Beeronomics conference. Beeronomics 2015: The Economics of Beer and Browing and the US Cider Industry, hosted by the Washington State University Impact Center and School of Economic Sciences and organized by project Co-PI Thomas Marsh, was slated for September 7-9, 2015, and will be further discussed in the subsequent project year's report. Numerous invited talks on previous and current research results were presented to industry stakeholders throughout U.S., including Oregon, Washington, California, Minnesota, Michigan, New York, Vermont, andWisconsin. Many of these are detailed as Conference Presentations in the Projects section of this report. In other cases, the conference itself is listed in the Other Projects section.PIs and Co-PIs responses to scores of individual requests for information and/or advising from stakeholders in Oregon, Washington, California, Minnesota, Michigan, New York, Vermont, Wisconsin, Pennsylvania, Ohio, Virginia, New Jersey, Connecticut, Massachusetts, Maine, Georgi, North Carolina, Maryland, and Delaware. The Great Lakes Hops Working Group has been formed and provides a forum for information exchange among hop growers in the Midwest and eastern US via monthly teleconferences.Results our emerging research have been pushed to friends of the Northwest Hop Information Network Facebook page when appropriate. Information on germplasm reaction to multiple strains of the powdery mildew pathogen was provided to all public sector breeding programs in the Pacific Northwest and three private breeding programs. Numerous informal discussions with breeding programs have occurred, and breeders have been encouraged to use germplasm identified as resistant through the powdery mildew screens. At least three breeding programs have or expressed they will make crosses with resistant materials identified herein. A framework for a website dedicated to the results from this SCRI project is under development in cooperation with Hop Growers of America and is planned for release during the second reporting year of this project. What do you plan to do during the next reporting period to accomplish the goals?Our approach is detailed in our Proposal Narrative and we are on track to accomplishing our goals via the methodologies discussed therein. Specifically with respect to the powdery mildew finding discussed in the "opportunities for training and professional development" section above,plans are to monitor and resample the hop yard in 2016, and to collect samples of the hop varieties there to test for trueness-to-type. Further research in Spring 2016 will focus upon the forecasting the period of ascospore release, as well as definition of the environmental conditions for ascosporic infection.

Impacts
What was accomplished under these goals? OBJECTIVE 1 Nitrogen rate studies were conducted in a commercial yard of cultivar Tomahawk in Washington and in experimental plots of cultivar Willamette in Oregon. In Washington,powdery mildew levels on leaves were generally unaffected by nitrogen fertilization rates over most of the growing season. However, in late summer powdery mildew levels on young leaves and cones were increased with increasing nitrogen rate, as were powdery mildew levels on basal foliage. Alpha-acids content and total oils were reduced with increasing nitrogen rate, although cone yield and overall alpha-acids yield tended to be greatest with intermediate rates of nitrogen (160 pounds per acre). Nitrate content of cones progressively increased with nitrogen rate. Powdery mildew did not develop in the plots in Oregon, although measurements of arthropod pests provided some evidence that nitrogen rate may increase abundance of spider mites, hop aphid, andhop looper. Yield was significantly impacted by nitrogen rate, with the highest yields observed with160 and 240 pounds of N per acre. Unlike the experiment in Washington with cv. Tomahawk, alpha-acids content of cones, yield of alpha-acids, and oils were not influenced by nitrogen rate. Cone nitrate content was directly related to nitrogen fertilization rate. These preliminary results indicate it may be possible to moderate powdery mildew and multiple arthropod pests, without negatively impacting cone yield and quality, by avoiding unduly high rates of nitrogen fertilizer. OBJECTIVE 2a Analysis was conducted on 11 years of historical data collected from experimental plots in Oregon to identify risk factors associated with spider mite damage to cones, and predict when cone damage is most likely to occur. Present analyses indicate that the best predictor of cone damage is cumulative mite-days in the upper canopy after bloom. Determinants of this variable were absence of spider mites in early spring, and lack of natural enemies in early and late spring. This finding indicates that early season management of spider mites may not be essential when biological control is active, and may even predispose yards to later outbreaks of spider mites when cone damage is most likely to occur. OBJECTIVE 2b In the fall of 2014,molecular biologist and entomologist Co-PI Laura Lavine, working with genetic researcher Fang Zhu, began toexpand molecular diagnostics including a comprehensive RNA-seq-based screen to identify resistance mechanisms from multiple populations of field-collected and laboratory selected spider mites (for bifenthrin, abamectin and bifenazate). We have successfully selectedlab populations forresistance ratios for bifenthrin (670 fold), abamectin (10,000 fold) and bifenazate (100,000 fold). Comprehensive sequencing of the transcriptomes of these resistant populations are underway.Throughout the winter of 2014-2015, Lavine, Zhu and their staffs sought to build increasingly robust protocols. The next step, begun during the spring and summer of this reporting year, is to identifythe mutations and changes in gene expression in our resistant laboratory strains, then develop a more direct sequencing protocol to first determine the frequency of these mutations and changes in gene expression in field-collected resistant populations of mites. We are targeting cytochrome P450s, carboxylesterases, glutathione-S-transferases, UDP-glycosyltransferases, and ABC transporters, but continue to be cognizant of other gene families that have been shown to have roles in detoxification. Results of three specific experiments are summarized as Data and Research Material (Product Type) entries in the Other Products section. OBJECTIVE 2c Historical data from 370 commercial hop yards collected during 2000 to 2015 was analyzed to identify risk factors linked to flag shoot occurrence and frequency. Analyses indicated that prior occurrence of flag shoots, disease levels in the previous season, pruning method, and winter temperature were associated with flag shoot development. Extensive surveys of hop yards in Oregon in 2014 and 2015 identified that landscape-level outbreaks of powdery mildew were associated with survival of the fungus in a small number of hop yards. In many instances, perennation of P. macularis was associated with chronic infection of highly susceptible cultivars when specific pruning practices were utilized in spring. Thus, focused management efforts in a subset of yards where overwintering is most probable may delay disease severity area-wide. Studies of ascocarp maturation and ascospore release were initiated in January 2015 with a local collection of cleistothecia. Ascospore release required free water and release events were distributed from March until late June, with a peak of released ascospores in May. OBJECTIVE 3 A series of inoculations with the powdery mildew pathogen were conducted under controlled conditions to determine: prevalence of virulence on the cultivar Cascade in the pathogen population ; relative growth of various isolates of the fungus on Cascade; and aggressiveness of Cascade-adapted strains of the fungus on other cultivars. All isolates with previously characterized race were able to infect Cascade and produce sporulating lesions. This pattern does not suggest the presence of a major R-gene in Cascade that limits growth of certain races of the fungus. Nearly all other isolates inoculated onto Cascade similarly caused disease. This demonstrated that most isolates of powdery mildew in Oregon and Washington can infect Cascade at some level, providing further evidence that powdery mildew resistance in Cascade is not immunity. Only 2 of 41 isolates (4.9%) obtained from Cascade were able to infect Nugget, indicating that Cascade-adapted strains of the fungus are distinct from strains that attack cultivars possessing R6. Isolates obtained from other cultivars, particularly those with V6 virulence, were poorly adapted to Cascade, further indicating a specific adaptation to quantitative resistance by Cascade-adapted strains of the pathogen. Cascade-adapted strains of the fungus caused greater disease than other strains of the pathogen only when inoculated to Cascade. Collectively, this work provides evidence that Cascade-adapted strains may infect other susceptible cultivars, but these strains are specifically adapted to Cascade. Multiple R-genes are predicted to provide qualitative resistance to Cascade-adapted strains of the fungus. Public breeding programs and private breeding programs were contacted during 2014 and 2015 and offers were made to screen germplasm for its reaction to various strains of the powdery mildew fungus. Two public and one private sector breeding program responded to the request and suggested or provided material to be screened. In addition to the germplasm of interest to the breeding programs, germplasm of interest because of downy mildew resistance or other traits were included as well. Females identified with high levels of resistance to all strains of the pathogen (to-date) were Comet, Crystal, Omega, Pride of Kent, Southern Brewer, and Sunbeam. Of particular interest are several males in the public domain with good levels of resistance to both powdery mildew and downy mildew, including 19005M, 21119M, and 64037M. OBJECTIVE 4 A summary of outreach activities is presented in the second subsection following: how results have been disseminated to communities of interest. OBJECTIVE 5 Planning for economic and sociological studies was conducted, including obtaining IRB approval and training for work with human subjects. OBJECTIVE 6 Students working on this project are detailed in the following subsection pertaining to opportunities for training and professional development.

Publications

  • Type: Other Status: Published Year Published: 2014 Citation: Walsh, D.B. and D. Groenendale. 2014. GLP Magnitude of Residue Trial for Famoxidone + Cymoxanil in Hop. Interregional Research Project 4.
  • Type: Other Status: Published Year Published: 2014 Citation: Walsh, D.B. and D. Groenendale. 2014. GLP Magnitude of Residue Trial for Pyraflufen-ethyl in Hop. Interregional Research Project 4.
  • Type: Journal Articles Status: Published Year Published: 2014 Citation: Woods, J. L., A.J. Dreves, D.G James, J.C Lee, D.B Walsh, &D.H. Gent. 2014. Development Biological Control of Tetranychus urticae (Acari: Tetranychidae) and Phorodon humuli (Hemiptera: Aphididae) in Oregon Hop Yards. 107:570-581. DOI: 10.1603/EC13488
  • Type: Book Chapters Status: Published Year Published: 2014 Citation: Zhu, F., C. Yingjun C, D.B. Walsh, & L.C. Lavine. 2014. Application of RNA Interference toward Insecticide Resistance. In. Insect Pest Management through Biochemical and Molecular Approaches. ISBN:978-1-63315-205-2: pp 595:619.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Walsh, D., & J. Barbour. Hop IPM in the US: Protecting the 26,000 acres that flavor 10 billion pints per year. Entomological Society of America, Minneapolis, MN.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2014 Citation: Walsh, D., Integrated management of arthropod pests on Pacific Northwest hops. Entomological Society of America. Portland, OR 2014
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Walsh D., & S. ONeal. 2015. Pesticide Residues and Biological Materials Present on Hops Grown Under a Variety of Input Regimes and in Beers Brewed Under a Variety of Hopping Regimes. Hop Growers of America Conference, San Diego, CA.
  • Type: Other Status: Published Year Published: 2015 Citation: ONeal, S.D. (ed) 2015. Pest Management Strategic Plan for U.S. Hops. http://www.ipmcenters.org/pmsp/pdf/US-hops-PMSP2015.pdf
  • Type: Journal Articles Status: Published Year Published: 2015 Citation: Gent, D. H. 2015. Quarantines, powdery mildew, and planting materials. HopNews letter. February 2015.
  • Type: Journal Articles Status: Published Year Published: 2015 Citation: Gent, D. H. 2015. Hop quarantines and powdery mildew. Oregon Association of Nurserymen Newsletter February 2015.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Gent, D. H., Twomey, M., Wolfenbarger, S., and Woods, J. 2015. Risk factors for perennation of Podosphaera macularis and landscape level development of hop powdery mildew. Phytopathology 105:S4.49.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Walsh, D.B. 2015. Miticide Resistance in Washington Hopyards. Presentation to American Hop Convention. Escondido, CA. January 22, 2015.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Walsh, D.B. 2015. Pesticide Residues and Biological Materials Present on Hops Grown Under a Variety of Input Regimes and in Beers Brewed Under a Variety of Hopping Regimes. Presentation to Hop Research Council Annual Summer Meeting. Yakima, WA. August 6, 2015.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Walsh, D.B. 2015. Integrated Pest Management of Arthropods on Hops. Presentation to Hop Research Council Annual Summer Meeting. Yakima, WA. August 5, 2015.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Walsh, D.B. 2015. IPM on Washington Hops. Presentation to Washington Hop Commission. Prosser, WA. June 17, 2015.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Walsh, D.B. 2015. Evaluation of Input Residue and Biological Material Impacts from Commercially and Organically Grown Hops on Different Commercial Beer Production Methods. Presentation to American Hop Convention. Escondido, CA. January 22, 2015.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Walsh, D.B. 2015. Miticide Resistance in Spider Mites in Hopyards. Washington Hop Growers Association. Yakima, WA. January 9, 2015.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Walsh, D.B. 2015. Reducing the Impact of Industry-Critical Insect and Disease Problems in Hop through Development of Preventive and Predictive Strategies. Washington Hop Growers Association. Yakima, WA. January 9, 2015.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Walsh, D.B. 2015. Insecticidal Efficacy Data in Hops and Wine Grapes. GS Long annual meeting. Yakima, WA. January 8, 2015.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2014 Citation: Walsh, D.B. 2015. IPM on Hops. Washington Hop Commission. Sunnyside, WA. October 15, 2014.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Gent, D. H. 2015. Downy mildew: identification, lifecycle, and management. Hop Summer Field Day, August 15, 2015 Arkansaw, WI.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Gent, D. H. 2015. Cultural practices, carbohydrate reserves, and yield. Hop Summer Field Day, August 14, 2015 Arkansaw, WI.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Gent, D. H. 2015. Downy mildew: identification, lifecycle, and management. Hop Summer Field Day, August 14, 2015 Waterloo, WI.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Gent, D. H. 2015. Cultural practices, carbohydrate reserves, and yield. Hop Summer Field Day, August 14, 2015 Waterloo, WI.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Gent, D. H. 2015. Best management practices for late season disease management. Yakima Chief-Hop Union. June 18, 2015 Toppenish, WA.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Gent, D. H. 2015. Cultural practices, carbohydrate reserves, and yield. Minnesota Hop Growers Association, March 7, 2015 Shakopee, MN.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Gent, D. H. 2015. Powdery mildew sampling. Yakima Chief-Hop Union. June 18, 2015 Toppenish, WA.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Gent, D. H. 2015. Downy mildew: identification, lifecycle, and management. Michigan Hop Growers Association, April 11, 2015 Grand Rapids, MI.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Gent, D. H. 2015. An introduction to powdery mildew. Michigan Hop Growers Association, April 11, 2015 Grand Rapids, MI.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Gent, D. H. 2015. Identification and management of priority diseases and pests. Minnesota Hop Growers Association, March 7, 2015 Shakopee, MN.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Gent, D. H. 2015. Overwintering biology of the hop powdery mildew fungus. Winter Meeting of the Hop Research Council. January 21, 2015, San Diego, CA.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Gent, D. H. 2015. Powdery mildew on hop varieties with R6: What happened and lessons learned. Winter Meeting of the Hop Research Council. January 21, 2015, San Diego, CA.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Twomey, M., and Gent, D. H. 2015. Overwintering of powdery mildew and area-wide epidemic development. January 21, 2015, San Diego, CA.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Twomey, M., and Gent, D. H. 2015. Overwintering biology of the hop powdery mildew fungus. Washington Hop Industry Annual Meeting. January 9, 2015,Yakima, WA.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Wolfenbarger, S. N., and Gent, D. H. 2015 A summary of powdery mildew on varieties with R6. Washington Hop Industry Annual Meeting. January 9, 2015,Yakima, WA.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Gent, D. H. 2015. 2013 and 2014 outbreaks of powdery mildew on Cascade. Washington Hop Industry Annual Meeting. January 9, 2015, Yakima, WA.
  • Type: Other Status: Published Year Published: 2015 Citation: Northeast Hop News newsletter was published in January, February, April, May, June, July and August. http://northeasthopalliance.org.
  • Type: Other Status: Published Year Published: 2014 Citation: Northeast Hop News Autumn Newsletter was published in November 2014. http://northeasthopalliance.org.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2014 Citation: Miller, S. 2014. Outlook for Hops 2015-2016 and Cost of Production for Hops. Presented at Cornell Hops Conference December 6, 2014. Morrison, NY.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Miller, S. 2015. What You Need to Know in Growing Hops. Cornell Cooperative Extension Beginning Hops Workshop. March 7, 30, 24, 27, and April 11, 2015. Various locations, NY.
  • Type: Books Status: Published Year Published: 2015 Citation: Miller, S. et al. 2015. 2015 Cornell Integrated Hops Production Guide. Cornell University Cooperative Extension.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Miller, S. 2015. Technologies and assistance for hop growers with physical challenges. Presented at AgriAbilities National Conference, April 14, 2015. Rochester, NY.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Miller, S. 2015. Maintaining quality in processed hops. Presented to FDA Inspectors conference June 12, 2015. Buffalo, NY.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Miller, S. 2015. Site selection, pest management, proper harvesting and processing equipment and techniques. Presented at the Summer Hop Conference on June 26. Portland, OR.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Zhu, F. Acaricide resistance of two-spotted spider mite in Pacific Northwest hop fields. Symposium: Molecular Entomology. ESA Pacific Branch meeting, Coeur d'Alene, ID, April 2015
  • Type: Conference Papers and Presentations Status: Published Year Published: 2014 Citation: Zhu, F., J. Bull, T. Piraneo, M. Morales, D. Walsh, and L. Lavine. Molecular mechanisms of Tetranychus urticae chemical adaptation in hops field. Annual Meeting of the Entomological Society of America, Portland, OR, November 2014
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Gadoury, D.M. 2015. Reducing the Impact of Industry-Critical Insect and Disease Problems in Hop through Development of Preventive and Predictive Strategies. New York Hort Expo. January 2015.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Gadoury, D.M. 2015. Reducing the Impact of Industry-Critical Insect and Disease Problems in Hop through Development of Preventive and Predictive Strategies. New York Natural and Organic Farmers Association. February 2015.