Source: OREGON STATE UNIVERSITY submitted to
BIOLOGY AND MANAGEMENT OF IRIS YELLOW SPOT VIRUS (IYSV), OTHER DISEASES, AND THRIPS IN ONIONS (FROM W1008)
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
TERMINATED
Funding Source
HATCH
Reporting Frequency
Annual
Accession No.
0232934
Grant No.
(N/A)
Project No.
ORE00576A
Proposal No.
(N/A)
Multistate No.
W-2008
Program Code
(N/A)
Project Start Date
Oct 1, 2012
Project End Date
Sep 30, 2017
Grant Year
(N/A)
Project Director
Shock, CL.
Recipient Organization
OREGON STATE UNIVERSITY
(N/A)
CORVALLIS,OR 97331
Performing Department
Malheur Experiment Station
Non Technical Summary
Onion (Allium cepa) is an economically important crop in the U.S., generating over 900 million dollars annually in farm receipts from 2005 to 2010. U.S. onion production area ranges from 60,000 to 70,000 hectares annually, with over 80% of the summer production (50,000 hectares) in the western states. Worldwide, 53 million metric tons of onion bulbs are harvested annually from nearly 3 million hectares. A significant portion of the U.S. and world supply of onion seed is produced in the western U.S., primarily in the Pacific Northwest. Onion thrips is the most serious pest of onion worldwide and it has become an even greater threat to onion as a vector of IYSV. Although onion thrips is the most common thrips pest of onion in the U.S., the western flower thrips (Frankliniella occidentalis) and the tobacco thrips (Frankliniella fusca) are also major pests of onion in parts of the western U.S. and southeastern U.S., respectively. Infestations of thrips in onion fields are managed primarily with frequent insecticide applications. In spite of chemical-intensive management, thrips continue to cause significant and increasing damage to onion because of widespread insecticide resistance to older insecticides that are still widely used by the. Therefore, thrips are a primary constraint to continued productive and sustainable onion production. Newer chemistries for thrips control continue to be released and incorporated into Integrated Pest Management (IPM) strategies. In addition to feeding injury caused by thrips, Iris yellow spot virus (IYSV), which is vectored by onion thrips, has emerged as a devastating new disease of onion. It causes widespread disease of onion and other Allium species and has been observed throughout the U.S. in bulb onion, chive, leek and garlic crops. Management of IYSV is challenging. Current management strategies include selection of cultivars less susceptible to the disease and/or the vector, increased and uniform plant population, selection of transplants free of IYSV and thrips, elimination of volunteer onions from previous crops and weeds during current cropping season, and separation of onion bulb and seed crops to break the green-bridge reservoirs of the thrips vector and the virus, Many growers also have implemented intensive thrips insecticide programs, which may provide some suppression of the disease. In spite of advances made in management of IYSV and thrips during the past 5 years the projected economic impacts of IYSV and thrips in the U.S. could reach 60 million dollars (10 percent loss) to 90 million dollars (15 percent loss). The use of 3 to 5 additional sprays for thrips control on 48,500 hectares of Allium crops per year adds 7.5 to 12.5 million dollars and uncalculatable environmental costs. The rapid and international spread of this disease emphasizes the need to continue to develop economical and effective IPM strategies. This project seeks to mitigate onion loss to thrips, virus, and other diseases to a multifaceted research and education program.
Animal Health Component
(N/A)
Research Effort Categories
Basic
(N/A)
Applied
(N/A)
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
2161451113025%
2161451102050%
2161451110125%
Knowledge Area
216 - Integrated Pest Management Systems;

Subject Of Investigation
1451 - Onion, garlic, leek, shallot;

Field Of Science
1130 - Entomology and acarology; 1101 - Virology; 1020 - Physiology;
Goals / Objectives
Objectives 1. Evaluate onion germplasm for greater levels of tolerance to IYSV, other pathogens and thrips. 2. Investigate thrips biology and IYSV epidemiology to improve management strategies. 3. Investigate the biology, ecology and epidemiology of other pathogens to improve management strategies. 4. Facilitate interaction and information transfer between W2008 participants, the onion industry and other stakeholders. Outputs 1. Improved breeding lines and cultivars will possess increased levels of tolerance to IYSV, thrips and other pathogens. New tolerant cultivars will become available to onion growers in all growing regions in the U.S. Concurrently, molecular markers for new resistance or tolerance alleles and QTL for these pathogens and pests will be generated from this project. 2. A detailed understanding of the extent and nature of the genetic diversity of IYSV in the U.S. will be obtained. New alternative methods of detection, inoculation, and/or screening environments for IYSV will be developed, which will serve as standardized protocols across the industry. Ultimately, the most appropriate inoculation method and the number and type of strains/isolates of IYSV and biotypes and species of thrips that need to be used for breeding and selection will be identified and standardized. Also, molecular diagnostic tools and genetic fingerprinting for detecting and monitoring pathogen and pest diversity in the U.S. will be utilized. 3. A macroarray that readily detects latent infections by bulb rot and foodborne pathogens at harvest will be developed allowing onion growers and other stakeholders to make informed storage management decisions based on an improved ability to predict the risk of storage rots and comtamination of foodborne pathogens. 4. New pathogens of onion will be identified, their importance determined and management strategies developed. 5. Cultural control tactics with emphasis on reduced nitrogen fertility will be developed for managing thrips, IYSV and bacterial diseases of onions. 6. A comprehensive biologically based and sustainable IPM program will be developed for managing IYSV, onion thrips and bacterial diseases of onions. 7. A more integrated point of exchange between researchers, growers and other interested parties will be developed and expanded using the www.alliumnet.com web site. 8. Joint meetings among W2008, NARC and NOA will be held.
Project Methods
We will continue to uniformly evaluate and report the reactions of onion entries (advanced breeding lines, cultivars, germplasm accessions) when exposed to IYSV and thrips populations under field and controlled conditions at cooperating sites with varying environmental conditions that support short-day, intermediate-day, and long-day onion types. Additional screening and identification of promising materials will continue to be promoted for use in onion cultivar improvement efforts by public and private onion breeders at cooperating sites throughout the U.S. It is important that cultivars that are selected for tolerance to IYSV and/or onion thrips are not especially susceptible to other diseases of onions, which could limit their usefulness commercially. Collaborators will conduct field, greenhouse and laboratory studies that will improve our understanding about thrips biology and IYSV epidemiology and lead to better management strategies for thrips and IYSV. These management strategies will be evaluated in trials at field stations and with cooperating growers. Dispersal of onion thrips in onion ecosystems is a key biological parameter that is not well known. Thrips dispersal will be examined through conventional sampling techniques such as visual counts of thrips in the surroundings of onion fields and on onion plants and numbers of adults captured on sticky cards. Cultural control tactics for thrips are needed and recent studies have identified reduced levels of nitrogen at planting as beneficial in reducing thrips populations without sacrificing yield. Research will continue to identify the overall role that nutrient management has on thrips populations. Use of live mulches, cover crops and foliar applications of kaolin are also among the cultural tactics that will be explored. As onion growers use more selective insecticides to manage thrips, natural thrips predators have become more common in onion fields. Research will identify natural enemy species that reduce thrips populations and strategies that will enhance natural predator populations and when these predators will have the greatest impact on suppressing thrips infestations. Detect foodborne pathogens associated with harvested onions: The DNA macroarray mentioned above is slated to include the detection of Salmonella spp. and E. coli, certain strains of which are human pathogens and can pose food safety risks. If either of these genres of bacteria is detected using the DNA macroarray, further tests can be conducted to determine if the strains pathogenic to humans are present and if they pose a food safety risk. A more integrated point of exchange between researchers, growers and other interested parties will be developed and expanded. W2008 members will continue to share results from this project and learn from colleagues involved with various research and extension projects.

Progress 10/01/12 to 09/30/17

Outputs
Target Audience:Onion Growers and Shippers Researchers Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Undergraduate students were trained in research protocols and learned about onion management and disease. How have the results been disseminated to communities of interest?The Oregon project has continued to transfer information pertinent to IYSV and thrips biology and management to growers, other onion industry parties, and the public through numerous meetings, field days, workshops, publications, and the internet. The Malheur Experiment Station hosted field days on July 12 and August 22. Results have also been presented at the Idaho-Malheur County Onion Growers Association Meeting, Pacific Northwest Vegetable Association Meeting, and the Treasure Valley Irrigation Conference. Research reports are available at www.cropinfo.net. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? Objective 1. Evaluate onion germplasm for greater levels of tolerance to Iris yellow spot virus (IYSV), other pathogens and thrips. Fifty nine direct-seeded yellow, white, and red onion varieties were evaluated in the field for plant disease, thrips, maturity, bolting, and bulb single centers. Out of storage the varieties were evaluated for yield, grade, and bulb decomposition. The varieties had substantial variation in thrips damage and ranges of IYSV, neck rot, black mold, and plate rot. Few bacterial diseases were noted. Seven transplanted varieties were evaluated in a similar fashion. Onion varieties were identified with lower amounts of thrips damage and bulb decomposition. Objective 2. Investigate thrips biology and IYSV epidemiology to improve management strategies. a. Evaluate different treatment sequences of insecticides for thrips and Iris yellow spot management. b. Evaluate new application methods for thrips and Iris yellow spot management. Insecticides remain the primary tool for thrips management. However, insecticide-based management faces difficulties because there is a limited set of registered insecticides with efficacy against onion thrips, and the ability of thrips populations to develop resistance to insecticides. Therefore, it remains important to assess the effectiveness of currently registered insecticides and to determine when during the season different insecticides may be used most effectively. It is also important to determine the effectiveness of new products and how they may be integrated into an overall thrips management program. Field trials to evaluate different insecticide management programs, with products applied in various sequences over the growing season. Twenty-four different treatment regimens in one trial and 12 in a second that included drip irrigation applications and foliar applications Our standard reference program of two applications of spirotetramat (Movento), followed by two of abamectin (Agrimek), two of spinetoram (Radiant) and two of methomyl (Lannate) still performed well under this season's conditions. As reported previously, Movento does not show good activity until after a second application is made. Applying Movento later in the season than the initial application window helps take advantage of its efficacy against larvae when populations peak in late June / early July. It is important to combine Movento with an adulticide with this type of use pattern so that dispersing adults do not cause excessive damage. Minecto Pro, which includes abamectin, the active ingredient in Agrimek, and cyantraniliprole, the active ingredient in Exirel and Verimark, provided slightly better control than Agrimek itself. Radiant remains the most effective insecticide in trials. It has good activity against adult and immature thrips. Because of this activity, it is a good option for use during peak thrips abundance. Results indicate methomyl may be losing some of its efficacy and growers may consider alternate chemistries when thrips are most abundant. Yields in programs with insecticides were higher than in the untreated control. Yields were low reflecting the late planting in 2017 and high temperatures during the season that stressed plants. These conditions also keep thrips populations higher than normal after the planned treatments ended in our 7 day interval trial. Our 10 day application interval trial had much higher yields, indicating the importance of continued monitoring of thrips populations through the season and treatment if necessary. Objective 3. Investigate the biology, ecology and epidemiology of other pathogens to improve management strategies. In 2014 and 2015 there was an increase in internal onion bulb decomposition of one or more scales in onion bulbs grown in the Treasure Valley. The organisms associated with these losses were bacterial rots and Fusarium proliferatum. Unlike neck rot or plate rot, this internal decomposition is difficult to detect externally, that can result in quality issues in marketing. We have thought that the internal decomposition is associated with one or more scales that do not finish forming completely into the neck, resulting in small gaps close to the neck. The 2014 and 2015 growing seasons were unusually warm, suggesting that excessive heat could be associated with the problems of internal decomposition. A. Trials sought to determine whether heat is a factor in bulb decomposition and whether or not treatments that increase or reduce the heat load in the soil and onion bulbs would affect the expression of internal bulb decomposition. The experimental design was a split-plot randomized complete block with six replicates. There were four treatments to effect temperature as the main plots and two varieties as split plots within each main plot. Each split plot was planted with 4 double rows wide and 27 ft long. The two varieties were 'Joaquin' and 'Granero' (Nunhems, Parma, ID). The four treatments were: 1) untreated check, 2) artificial heat, 3) kaolinite, and 4) straw mulch. Kaolinite and straw mulch were treatments that attempted to reduce the heat load on the onions. The artificial heat was applied using one heat cable. The treatments directly affected onion bulb temperature and soil temperature. The development of internal decomposition was associated with higher bulb and soil temperature. B. To learn more about bulb internal quality problems, this trial sought to determine when incomplete scale, dry scale, and internal decomposition can be observed and how quickly they increase. Onions in each plot were evaluated weekly in the field starting July 7 and ending September 15. After harvest, the onions from each plot were evaluated out of storage monthly starting in mid-November. Five consecutive bulbs from each single row in the four-double-row plot were cut longitudinally and rated for the presence of incomplete scales, dry scales, and internal decay caused by, bacteria, neck rot, black mold, or Fusarium proliferatum. Incomplete scales were defined as scales that had more than 0.25 inch from the center of the neck missing or any part missing lower down on the scale. Dry scales were defined as scales a small dry scale inside the bulb either near the top of the neck or lower down on the scale. Bulbs from the first two single rows in each plot had the number of leaves counted and the diameter measured. Incomplete and dry scale started occurring in late July and internal decomposition in August. C. Chlorine and diatomaceous earth for control of internal decay of onion. The experimental design was a randomized complete block with four treatments and six replicates. A bleach solution was made by dissolving granular calcium hypochlorite (Ca(ClO)2 ,49% Cl) in water to make a 100-ppm Cl concentration. The solution was broadcast at 44.5 gallons/acre. The diatomaceous earth was broadcast at 37 lb/acre in 148 gal water/acre. Both solutions were broadcast over the four onion double rows three times during bulb maturation and curing. Onions were evaluated out of storage and were evaluated for the presence of incomplete scales, dry scales, and internal decay from bacteria, Fusarium proliferatum, black mold, or neck rot. The amounts of internal decomposition were very low in every treatment, including the untreated check treatment.

Publications

  • Type: Conference Papers and Presentations Status: Other Year Published: 2017 Citation: Shock, C.C. 2017. Creation and adoption of smart agriculture innovations to cope with climatic uncertainty. Keynote address at the International Conference on Biodiversity, Climate Change Assessment and Impacts on Livelihood, Hotel Crown Plaza  Soaltee, Kathmandu, Nepal, 10-12 January.
  • Type: Conference Papers and Presentations Status: Other Year Published: 2017 Citation: Shock, C.C. 2017. Irrigation management for climate-smart agriculture. Keynote address at the International Conference on Technological Advances in Climate-Smart Agriculture and Sustainability (TACSAS 2017). Shri Guru Gobind Singhji Institute of Engineering and Technology, Nanded, India, 16-18 January.
  • Type: Conference Papers and Presentations Status: Other Year Published: 2017 Citation: Shock, C.C. 2017. Climate-smart agriculture. Jain Irrigations Systems, Jalgaon, India, 24 January.
  • Type: Conference Papers and Presentations Status: Other Year Published: 2017 Citation: Shock, C.C. 2017. Are field experiments easy? How to design, manage, and evaluate field experiments. China Agricultural University. Beijing, China. 6 June.
  • Type: Conference Papers and Presentations Status: Other Year Published: 2017 Citation: Nault, B.A., S.R. Reitz, T.D. Waters. Current and Future Management of Onion Thrips-Transmitted Iris yellow spot virus (IYSV) in Onion. P-IE Section Symposium: Inspiring a New Cadre of Vegetable Specialists By Sharing Expertise Related to Piercing-Sucking Insects of Economic Importance in Vegetable Production. Entomological Society of America, Denver, CO, November 2017.
  • Type: Conference Papers and Presentations Status: Other Year Published: 2017 Citation: Shock, C.C., F.X. Wang, A.D. Campbell, and H. Dominguez-Aguire. 2017. Triggering Drip Irrigation Onset by Soil Water Tension. International Irrigation Show, Orlando, Florida, 7 November.
  • Type: Conference Papers and Presentations Status: Other Year Published: 2017 Citation: Foley, K., C.C. Shock, and M. Santelmann. 2017. Drivers and barriers to producers voluntary adoption of practices that protect water quality. International Irrigation Show, Orlando, Florida, 8 November.
  • Type: Conference Papers and Presentations Status: Other Year Published: 2017 Citation: Shock, C.C. and F.X. Wang. 2017. Controlling Irrigation Onset by Soil Water Tension. Annual meeting of the American Society of Horticultural Science, Waikoloa, HI, 22 September.
  • Type: Conference Papers and Presentations Status: Other Year Published: 2017 Citation: Foley, K., C.C. Shock, and M. Santelmann. 2017. Drivers and barriers to producers voluntary adoption of practices that protect water quality. Annual meeting of the American Society of Horticultural Science, Waikoloa, HI, 21 September.
  • Type: Conference Papers and Presentations Status: Other Year Published: 2017 Citation: Shock, C.C., E.B.G. Feibert, and N.L. Shaw. 2017. Oregon Report to W3128, Scaling Microirrigation Technologies to Address Global Water Challenges. Annual meeting of the W3128 working group, 5 November, Orlando, Florida.
  • Type: Conference Papers and Presentations Status: Other Year Published: 2017 Citation: Shock, C.C. 2017. Precision irrigation can optimize yields and reduce input costs. Hermiston Farm Fair, Hermiston, Oregon. 30 November.
  • Type: Conference Papers and Presentations Status: Other Year Published: 2017 Citation: Shock, C.C., S.R. Reitz, E. Feibert, A. Rivera, H. Kreeft, and J. Klauzer. 2017. Overview of research on the Food Safety Modernization Act. Idaho-Eastern Oregon Onion Growers Association Annual Meeting, Ontario, OR. 7 February.
  • Type: Conference Papers and Presentations Status: Other Year Published: 2017 Citation: Reitz, S., C.C. Shock, E.B.G. Feibert, A. Rivera, L.D. Saunders, and E. Jemmett. 2017. Thrips and iris yellow spot virus management in the Treasure Valley. Idaho-Eastern Onion Growers Association Annual Meeting, Ontario, OR. 7 February.
  • Type: Conference Papers and Presentations Status: Other Year Published: 2017 Citation: Shock, C.C. 2017. Drip irrigation for onion: growers adoption of innovations. Clearwater Supply Annual Drip irrigation Meeting, 8 January, Ontario, Oregon.
  • Type: Other Status: Published Year Published: 2017 Citation: Shock, C. C., Feibert, E. B. G., Rivera, A., and Saunders, L. D. 2017. 2016 onion variety trials. p 14-31. In Shock C.C. (Ed.) Oregon State University Agricultural Experiment Station, Malheur Experiment Station Annual Report 2016, Department of Crop and Soil Science Ext/CrS 157.
  • Type: Other Status: Published Year Published: 2017 Citation: Shock, C. C., Feibert, E. B. G., Rivera, A., Saunders, L. D., and Simerly, B. 2017. Onion Production from Transplants in 2016. p 32-42. In Shock C.C. (Ed.) Oregon State University Agricultural Experiment Station, Malheur Experiment Station Annual Report 2016, Department of Crop and Soil Science Ext/CrS 157.
  • Type: Other Status: Published Year Published: 2017 Citation: Shock, C. C., Feibert, E. B. G., Rivera, A., and Saunders, L. D. 2017. Onion internal quality in response to artificial heat and heat mitigation during bulb development. p 43-53. In Shock C.C. (Ed.) Oregon State University Agricultural Experiment Station, Malheur Experiment Station Annual Report 2016, Department of Crop and Soil Science Ext/CrS 157.
  • Type: Other Status: Published Year Published: 2017 Citation: Reitz, S. R., Noble, J., Shock, C. C., Feibert, E. B. G., Rivera, A., and Saunders, L. D. 2017. Thrips and iris yellow spot virus management in the Treasure Valley. p 99-119. In Shock C.C. (Ed.) Oregon State University Agricultural Experiment Station, Malheur Experiment Station Annual Report 2016, Department of Crop and Soil Science Ext/CrS 157.
  • Type: Other Status: Published Year Published: 2017 Citation: Buhrig, W., Shock, C. C., Feibert, E. B. G., and Saunders, L. D. 2017. Wireless sensor network for on farm soil moisture data acquisition and irrigation scheduling. p 231-237. In Shock C.C. (Ed.) Oregon State University Agricultural Experiment Station, Malheur Experiment Station Annual Report 2016, Department of Crop and Soil Science Ext/CrS 157.
  • Type: Other Status: Published Year Published: 2017 Citation: Shock, C. C., Feibert, E. B. G., Rivera, A., and Saunders, L. D. 2017. Timing of Internal quality problems in onion bulbs. p 54-62. In Shock C.C. (Ed.) Oregon State University Agricultural Experiment Station, Malheur Experiment Station Annual Report 2016, Department of Crop and Soil Science Ext/CrS 157.
  • Type: Other Status: Published Year Published: 2017 Citation: Shock, C. C., Feibert, E. B. G., Rivera, A., and Saunders, L. D. 2017. Evaluation of chlorine and diatomaceous earth for control of internal decay in onion bulbs. p 63-66. In Shock C.C. (Ed.) Oregon State University Agricultural Experiment Station, Malheur Experiment Station Annual Report 2016, Department of Crop and Soil Science Ext/CrS 157.
  • Type: Other Status: Published Year Published: 2017 Citation: Reitz, S. R., Shock, C. C., Feibert, E. B. G., Rivera, A., Saunders, L. D., Kreeft, H., and Klauzer, J. 2017. Safe production of onion  2016, understanding the fate of Escherichia coli in the soil. p 82-92. In Shock C.C. (Ed.) Oregon State University Agricultural Experiment Station, Malheur Experiment Station Annual Report 2016, Department of Crop and Soil Science Ext/CrS 157.
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Zhao, X., S. R. Reitz, H. Yuan, Z. Lei, D. R. Paini, and Y. Gao. 2017. Pesticide-mediated intraspecific competition between local and invasive thrips pests. Nature Scientific Reports. 7:40512|DOI: 10.1038/srep40512.
  • Type: Conference Papers and Presentations Status: Other Year Published: 2017 Citation: Reitz, S.R. Emerging Developments in Insecticide Resistance Management for Thrips. Beijing Academy of Agriculture and Forestry Sciences. Beijing, China. 27 November 2017.


Progress 10/01/15 to 09/30/16

Outputs
Target Audience:Onion Growers and Shippers Researchers Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Undergraduate students were trained in research protocols and learned about onion management and disease. How have the results been disseminated to communities of interest?The Oregon project has continued to transfer information pertinent to IYSV and thrips biology and management to growers, other onion industry parties, and the public through numerous meetings, field days, workshops, publications, and the internet. The Malheur Experiment Station hosted field days on July 13 and August 30. Results have also been presented at the Idaho-Malheur County Onion Growers Association Meeting, Pacific Northwest Vegetable Association Meeting, and the Treasure Valley Irrigation Conference. Research reports are available at www.cropinfo.net. What do you plan to do during the next reporting period to accomplish the goals?We plan to continue the same activities reported above in our accomplishments of goals.

Impacts
What was accomplished under these goals? Objective 1. Evaluate onion germplasm for greater levels of tolerance to Iris yellow spot virus (IYSV), other pathogens and thrips. Direct-seeded yellow, white, and red onion varieties were evaluated in the field for plant disease, thrips, maturity, bolting, and bulb single centers. Out of storage, the varieties were evaluated for yield, grade, and bulb decomposition. Eight early-season yellow varieties and one early-season red variety were planted in March and were harvested and graded in early August. Forty-seven full-season varieties (39 yellow, 5 red, and 3 white) were planted in March, harvested in September, and will be graded out of storage in January 2017. Each year, growers and seed industry representatives have the opportunity to examine the varieties at our annual Onion Variety Field Day in late August and during bulb evaluations in early January. Onion varieties are evaluated objectively for bolting, yield, grade, single centers, and storability. Varieties are evaluated subjectively for maturity, thrips leaf damage, iris yellow spot virus, bulb shape, bulb shape uniformity, flesh brightness, and skin color and retention. Objective 2. Investigate thrips biology and IYSV epidemiology to improve management strategies. Onion thrips and IYSV management were evaluated in field trials with 36 insecticide regimes. Product recommendations included using Movento at the start of programs. However, when management needs to begin by May, delaying use of Movento by 1-2 weeks can improve management of peak thrips populations at the end of June and early July. Objective 3. Investigate the biology, ecology and epidemiology of other pathogens to improve management strategies. A major portion of the Food Safety Modernization Act's Produce Safety Rule focuses on the microbiological quality of irrigation water. Multi-year studies on the effect of contaminated irrigation water on the relative fate of generic Escherichia coli in water, in soil, and on onions during growth, curing, harvesting, and storage were completed. Drip or furrow irrigation did not appear to pose a significant risk for E. coli contamination of dry bulb onions. E. coli rapidly died-off in the soil and on onion exteriors in the field. Plastic containers did not provide added food safety value compared with wooden boxes for storage of dry bulb onions. Chlorine dioxide showed promise to remediate microbial contamination of water used in drip irrigation, if needed for compliance with water quality standards. Objective 4. Facilitate interaction and information transfer between W2008 participants, the onion industry and other stakeholders. In a new area-wide monitoring program, Treasure Valley growers received weekly reports of thrips abundance and IYSV incidence collected from commercial fields throughout the valley. This information enabled growers to better assess risks of thrips and IYSV in their growing regions.

Publications

  • Type: Other Status: Published Year Published: 2016 Citation: Reitz, S.R., C.S. Cramer, C.C. Shock, E.B.G. Feibert, A. Rivera, and L. Saunders. 2016. Evaluation of new onion lines for resistance to onion thrips and Iris yellow spot virus. Pp. 170-174, In: 2015 Malheur Exp. Stn Annu. Rep. OR State Univ. Agric. Expt. Stn. Circ. 156.
  • Type: Journal Articles Status: Published Year Published: 2016 Citation: Shock, C.C., S.R. Reitz, R.A. Roncarati, H. Kreeft, B.M. Shock, and J. Klauzer. 2016. Drip vs. furrow irrigation in the delivery of Escherichia coli to onions. Appl. Eng. Agric. 32:235-244.
  • Type: Conference Papers and Presentations Status: Other Year Published: 2016 Citation: Shock, C.C. 2016. Drip irrigation of onions. 5to Congreso de Cebollas 2016. Aguas Calientes, Mexico. 26 May 2016.
  • Type: Conference Papers and Presentations Status: Other Year Published: 2016 Citation: Shock, C.C. 2016. Optimizing horticultural production using drip irrigation. Conf. Water Energy Innov. Food Security Env. Sust., Chinese Agric. Univ., Beijing, China, 2 Jun. 2016.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Reitz, S.R. C.C. Shock, H. Kreeft, J.C. Klauzer, and A. Rivera. 2016. Dry bulb onion storage in sterilized plastic crates compared to storage in old wooden boxes. Amer. Soc. Hort. Sci., Atlanta, GA. 10 Aug. 2016. https://ashs.confex.com/ashs/2016/meetingapp.cgi/Paper/25083.
  • Type: Other Status: Published Year Published: 2016 Citation: Reitz, S.R., C.C. Shock, E.B.G. Feibert, A. Rivera, H. Kreeft, and J. Klauzer. 2016. Dry bulb onion storage in sterilized plastic crates compared to storage in old wooden boxes. Pp. 123-132 In: Oregon State University Agricultural Experiment Station, Malheur Experiment Station Annual Report 2015, Shock C.C., Ed., Department of Crop and Soil Science Ext/CrS 156.
  • Type: Other Status: Published Year Published: 2016 Citation: Reitz, S.R., C.C. Shock, H. Kreeft, and J. Klauzer. 2016. Chlorine dioxide injection through drip irrigation reduces E. coli. Pp. 133-139 In: Oregon State University Agricultural Experiment Station, Malheur Experiment Station Annual Report 2015, Shock C.C., Ed., Department of Crop and Soil Science Ext/CrS 156.
  • Type: Other Status: Published Year Published: 2016 Citation: Reitz, S.R., C.C. Shock, E.B.G. Feibert, A. Rivera, L.D. Saunders, H. Kreeft, and E. Jemmett. 2016. Controlling E. coli with in-field application of copper fungicides. Pp. 140-144 In: Oregon State University Agricultural Experiment Station, Malheur Experiment Station Annual Report 2015, Shock C.C., Ed., Department of Crop and Soil Science Ext/CrS 156.
  • Type: Other Status: Published Year Published: 2016 Citation: Reitz, S., C.C. Shock, E.B.G. Feibert, A. Rivera, L.D. Saunders, and E. Jemmett. 2016. Evaluation of insecticides and insecticide use patterns for management of thrips and iris yellow spot virus. Pp. 145-169 In: Oregon State University Agricultural Experiment Station, Malheur Experiment Station Annual Report 2015, Shock C.C., Ed., Department of Crop and Soil Science Ext/CrS 156.
  • Type: Other Status: Published Year Published: 2016 Citation: Shock, C.C., E.B.G. Feibert, A. Rivera and L.D. Saunders. 2016. 2015 Onion variety trials. Pp. 11-27 In: Oregon State University Agricultural Experiment Station, Malheur Experiment Station Annual Report 2015, Shock C.C., Ed., Department of Crop and Soil Science Ext/CrS 156.
  • Type: Other Status: Published Year Published: 2016 Citation: Shock, C.C., E.B.G. Feibert, A. Rivera, L.D. Saunders and B. Simerly. 2016. Onion production from transplants. Pp. 28-37 In: Oregon State University Agricultural Experiment Station, Malheur Experiment Station Annual Report 2015, Shock C.C., Ed., Department of Crop and Soil Science Ext/CrS 156.
  • Type: Other Status: Published Year Published: 2016 Citation: Shock, C.C., E.B.G. Feibert, A. Rivera, and L.D. Saunders. 2016. Onion response to in-season nutrient supplementation strategies and at-planting phosphorus application in 2015. Pp. 38-53 In: Oregon State University Agricultural Experiment Station, Malheur Experiment Station Annual Report 2015, Shock C.C., Ed., Department of Crop and Soil Science Ext/CrS 156.
  • Type: Other Status: Published Year Published: 2016 Citation: Shock, C.C., E.B.G. Feibert, A. Rivera, L.D. Saunders, and D. Huenefeld. 2016. Evaluation of Kelpak and Greenfeed in onion production. Pp. 54-60 In: Oregon State University Agricultural Experiment Station, Malheur Experiment Station Annual Report 2015, Shock C.C., Ed., Department of Crop and Soil Science Ext/CrS 156.
  • Type: Other Status: Published Year Published: 2016 Citation: Shock, C.C., S.R. Reitz, E.B.G. Feibert, A. Rivera, L.D. Saunders, H. Kreeft, and J. Klauzer. 2016. Soil filtering reduces onion bulb exposure to E. coli from irrigation water. Pp. 104-122 In: Oregon State University Agricultural Experiment Station, Malheur Experiment Station Annual Report 2015, Shock C.C., Ed., Department of Crop and Soil Science Ext/CrS 156.


Progress 10/01/14 to 09/30/15

Outputs
Target Audience:Onion Growers and Shippers Researchers Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Undergraduate students were trained in research protocols and learned about onion management and disease. How have the results been disseminated to communities of interest?The Oregon project has continued to transfer information pertinent to IYSV and thrips biology and management to growers, other onion industry parties, and the public through numerous meetings, field days, workshops, publications, and the internet. The Malheur Experiment Station hosted field days on July 8 and August 25 and a stop on the NOA tour on July 17. Results have also been presented at the Idaho-Malheur County Onion Growers Association Meeting, Pacific Northwest Vegetable Association Meeting, and the Treasure Valley Irrigation Conference. Research reports are available at www.cropinfo.net. What do you plan to do during the next reporting period to accomplish the goals?We plan to continue the same activities reported above in our accomplishments of goals.

Impacts
What was accomplished under these goals? 1. Evaluate onion germplasm for greater levels of tolerance to Iris yellow spot virus (IYSV), other pathogens and thrips. Early maturity and full season onion variety trials were conducted in 2015 with support from the Idaho-Eastern Oregon Onion Committee and various seed companies. The trials were grown under drip irrigation. All varieties were evaluated for their yield, maturity and susceptibility to thrips damage and IYSV. Varieties had significant differences in IYSV in 2015. The scales of many of the onion bulbs failed to close at the neck. Bulbs tended to have internal decomposition. In order to examine possible variety influences and the prevalence of internal disease, 50 onions from three replicates of each variety were cut vertically and rated for neck closure and internal pathogens. Thrips populations and IYSV incidence were compared among four experimental breeding lines from Chris Cramer, NMSU, and three commercial cultivars. The experimental lines tended to have lower populations of thrips and IYSV severity than the commercial cultivars. 2. Investigate thrips biology and IYSV epidemiology to improve management strategies. Two insecticide rotation trials were conducted to evaluate the effectiveness of various insecticides in managing thrips and IYSV. One trial included all foliar applied insecticides, and another trial featured insecticides applied through drip irrigation and by ground application. Movento and Agri-mek were effective in early season thrips management. Using moderately efficacious insecticides, such as azadirachtin at the beginning of a spray program, has been encouraging. This use pattern allows applications of Movento to be made later in the season so that Movento Radiant remains the most effective insecticide for mid to late season thrips management. Programs with drip applied products performed as well as foliar applied products. Drip applications may reduce grower expenses by reducing overall application costs. 3. Investigate the biology, ecology and epidemiology of other pathogens to improve management strategies. The Food and Drug Administration published the Food Safety Modernization Act rules regarding produce safety in November 2015. In anticipation of these rules, research on onion production in relation to food safety continued in 2015 at the Malheur Experiment Station. A replicated study was conducted in 2015 to compare the roles of wooden and plastic storage containers on contamination of onion bulbs with generic Escherichia coli, the FDA indicator for potential microbial contamination. E. coli levels of onions grown in furrow-irrigated plots using surface irrigation water with enhanced E. coli levels and harvested into old wooden boxes and sterilized plastic crates were compared with E. coli levels of onions grown in five replicated drip-irrigated plots using well water with no detectable E. coli and harvested into similar containers. After 6 weeks in storage, onions were prepared for shipment (packed out) through removal of loose skin, roots and soil. Regardless of irrigation source, neither onions stored in plastic nor in wooden containers had detectable E. coli on the bulb exteriors or interiors. These results are consistent with our previous trials and indicate that storage container material does not affect the likelihood of E. coli contamination of dry bulb onions. In 2015 we repeated field studies originally conducted in 2013 and 2014 to evaluate if surface irrigation systems reusing water may deliver bacteria to dry bulb onions. We tested the potential for furrow irrigation using canal water with moderate or high levels of E. coli contamination and drip irrigation using canal water and well water free of E. coli to deliver E. coli to onion bulbs. The four irrigation systems (replicated five times) applied water to onion grown on silt loam soil. Water was sampled hourly for E. coli and the lateral movement of E. coli in the soil solution was tracked by soil samples and Sterile Soil Solution Samplers at the end of irrigations. Onions were sampled for E. coli contamination. Consistent with previous results, furrow irrigation delivered E. coli to the soil immediately adjacent to the onion bulbs. E. coli movement under drip irrigation was mostly confined to near the drip tape and very little reached the onion bulbs, indicating that drip irrigation did not directly deliver E. coli to onions. In the Treasure Valley, surface irrigation water is commonly used for drip irrigation. We evaluated the use of chlorine dioxide as an antimicrobial for use in drip irrigation systems to reduce bacterial loads in surface irrigation water. Growers often routinely use injections of chlorine dioxide at the end of irrigation cycles to control the growth of algae in drip irrigation lines. We found that current rates of chlorine dioxide for drip line maintenance (3 ppm) virtually eliminate E. coli. Lower rates (1 ppm) also significantly reduce E. coli levels far below FDA standards of 126 CFU / 100 ml. 4. Facilitate interaction and information transfer between W2008 participants, the onion industry and other stakeholders. The Oregon project has continued to transfer information pertinent to IYSV and thrips biology and management to growers, other onion industry parties, and the public through numerous meetings, field days, workshops, publications, and the internet. The Malheur Experiment Station hosted field days on July 8 and August 25 and a stop on the NOA tour on July 17. Results have also been presented at the Idaho-Malheur County Onion Growers Association Meeting, Pacific Northwest Vegetable Association Meeting, and the Treasure Valley Irrigation Conference. Research reports are available at www.cropinfo.net.

Publications

  • Type: Conference Papers and Presentations Status: Other Year Published: 2015 Citation: Shock, C.C., S.R. Reitz, R.A. Roncarati, H. Kreeft, B.M. Shock, and J. Klauzer. 2015. Drip vs furrow irrigation in the delivery of Escherichia coli to fresh produce. 2015 ASABE/IA Irrigation Symposium. International Irrigation Show, Long Beach, CA. November 11.
  • Type: Conference Papers and Presentations Status: Other Year Published: 2015 Citation: Shock, C.C., E.B.G. Feibert, and L.D. Saunders. 2015. Response of onion yield, grade, and financial return to plant population and irrigation system. Annual Meeting of the American Society of Horticultural Science, Sheraton Hotel, New Orleans, LA. August 7.
  • Type: Other Status: Published Year Published: 2015 Citation: Shock, C.C., E.B.G. Feibert, and L.D. Saunders. 2015. 2014 Onion variety trials. p 11-34 In Shock C.C. (Ed.) Oregon State University Agricultural Experiment Station, Malheur Experiment Station Annual Report 2014, Department of Crop and Soil Science Ext/CrS 152.
  • Type: Other Status: Published Year Published: 2015 Citation: Shock, C.C., E.B.G. Feibert, and L.D. Saunders. 2015. Onion production from transplants. p 35-41 In Shock C.C. (Ed.) Oregon State University Agricultural Experiment Station, Malheur Experiment Station Annual Report 2014, Department of Crop and Soil Science Ext/CrS 152.
  • Type: Other Status: Published Year Published: 2015 Citation: Shock, C.C., J.M. Pinto, E.B.G. Feibert, and L.D. Saunders. 2015. Onion response to phosphorus application strategies and in-season nutrient supplementation, 2014. p 42-59 In Shock C.C. (Ed.) Oregon State University Agricultural Experiment Station, Malheur Experiment Station Annual Report 2014, Department of Crop and Soil Science Ext/CrS 152.
  • Type: Other Status: Published Year Published: 2015 Citation: Pinto, J.M., C.C. Shock, E.B.G. Feibert, L.D. Saunders, and D. Beck. 2015. Onion response to late-season water stress and high nitrogen under two plant populations. p 60-74 In Shock C.C. (Ed.) Oregon State University Agricultural Experiment Station, Malheur Experiment Station Annual Report 2014, Department of Crop and Soil Science Ext/CrS 152.
  • Type: Other Status: Published Year Published: 2015 Citation: Shock, C.C., J.M. Pinto, E.B.G. Feibert, and L.D. Saunders. 2015. Onion response to irrigation criteria for two distinct market opportunities. 2014. p 75-91 In Shock C.C. (Ed.) Oregon State University Agricultural Experiment Station, Malheur Experiment Station Annual Report 2014, Department of Crop and Soil Science Ext/CrS 152.
  • Type: Other Status: Published Year Published: 2015 Citation: Shock, C.C., E.B.G. Feibert, and L.D. Saunders. 2015. Evaluation of Kelpak� and Dominate� in onion production. 2014. p 92-97 In Shock C.C. (Ed.) Oregon State University Agricultural Experiment Station, Malheur Experiment Station Annual Report 2014, Department of Crop and Soil Science Ext/CrS 152.
  • Type: Other Status: Other Year Published: 2015 Citation: Shock, C.C., S.R. Reitz, R.A. Roncarati, H. Kreeft, J. Klauzer, E.B.G. Feibert, and L.D. Saunders. 2015. Movement of Escherichia coli in soil as applied in irrigation water. p 131-148 In Shock C.C. (Ed.) Oregon State University Agricultural Experiment Station, Malheur Experiment Station Annual Report 2014, Department of Crop and Soil Science Ext/CrS 152.
  • Type: Other Status: Published Year Published: 2015 Citation: Shock, C.C., R.A. Roncarati, S.R. Reitz, E.B.G. Feibert, H. Kreeft, and J. Klauzer. 2015. Dry bulb onion storage in sterilized plastic crates compared to storage in old wooden boxes. p 149-160 In Shock C.C. (Ed.) Oregon State University Agricultural Experiment Station, Malheur Experiment Station Annual Report 2014, Department of Crop and Soil Science Ext/CrS 152.
  • Type: Other Status: Published Year Published: 2015 Citation: Reitz, S.R., C.C. Shock, R.A. Roncarati, E.B.G. Feibert, and H. Kreeft. 2015. Survival of Escherichia coli on onion during field curing and packout. p 161-169 In Shock C.C. (Ed.) Oregon State University Agricultural Experiment Station, Malheur Experiment Station Annual Report 2014, Department of Crop and Soil Science Ext/CrS 152.
  • Type: Other Status: Published Year Published: 2015 Citation: Reitz, S.R., R.A. Roncarati, C.C. Shock, H. Kreeft, and J. Klauzer. 2015. Chlorine dioxide injection through drip irrigation reduces Escherichia coli. p 170-178 In Shock C.C. (Ed.) Oregon State University Agricultural Experiment Station, Malheur Experiment Station Annual Report 2014, Department of Crop and Soil Science Ext/CrS 152.
  • Type: Other Status: Published Year Published: 2015 Citation: Reitz, S.R., C.C. Shock, R.A. Roncarati, E.B.G. Feibert, and H. Kreeft. 2015. Effects of copper sulfate on levels of Escherichia coli in irrigation canal water. p 179-183 In Shock C.C. (Ed.) Oregon State University Agricultural Experiment Station, Malheur Experiment Station Annual Report 2014, Department of Crop and Soil Science Ext/CrS 152.
  • Type: Other Status: Published Year Published: 2015 Citation: Reitz, S.R., C.C. Shock, R.A. Roncarati, E.B.G. Feibert, L.D. Saunders, H. Kreeft, and E. Jemmett. 2015. Controlling Escherichia coli with in-field application of copper fungicides. p 184-186 In Shock C.C. (Ed.) Oregon State University Agricultural Experiment Station, Malheur Experiment Station Annual Report 2014, Department of Crop and Soil Science Ext/CrS 152.
  • Type: Other Status: Published Year Published: 2015 Citation: Reitz, S., C.C. Shock, E.B.G. Feibert, L.D. Saunders, and E. Jemmett. 2015. Evaluation of Insecticides and Insecticide Use Patterns for management of thrips and Iris Yellow Spot Virus. p 187-205 In Shock C.C. (Ed.) Oregon State University Agricultural Experiment Station, Malheur Experiment Station Annual Report 2014, Department of Crop and Soil Science Ext/CrS 152.
  • Type: Other Status: Published Year Published: 2015 Citation: Reitz, S., C.C. Shock, E.B.G. Feibert, L.D. Saunders and E. Jemmett. 2015. New fungicide treatments for pink root management and plant health in onion. p 206-210 In Shock C.C. (Ed.) Oregon State University Agricultural Experiment Station, Malheur Experiment Station Annual Report 2013, Department of Crop and Soil Science Ext/CrS 149.
  • Type: Journal Articles Status: Published Year Published: 2015 Citation: Shock, C.C., E.B.G. Feibert, A. Rivera, L.D. Saunders. 2015. Response of onion yield, grade, and financial return to plant population and irrigation system. HortScience 50(9):1312-1318.
  • Type: Other Status: Published Year Published: 2015 Citation: Shock, C.C., J.M. Pinto, E.B.G. Feibert, and C.B. Shock. 2015. Optimal irrigation criteria for drip irrigated onions. Growing Produce. March 24, 2015.
  • Type: Conference Papers and Presentations Status: Other Year Published: 2015 Citation: Shock, C.C. 2015. Development of drip irrigation for onions. China Agriculture University, Beijing, China. September 25.
  • Type: Conference Papers and Presentations Status: Other Year Published: 2015 Citation: Shock, C.C. and E.B.G. Feibert. 2015. The development of drip irrigation for onion production. Universidade Federal de Lavras, Lavras, Minas Gerais, Brazil. March 23.
  • Type: Conference Papers and Presentations Status: Other Year Published: 2015 Citation: Shock, C.C., E.B.G. Feibert, S. Reitz, A. Rivera, R. Roncarati, H. Kreeft, J.M. Pinto, B.M. Shock, and L.D. Saunders. 2015. Avoiding irrigation-induced bacterial contamination of vegetable crops. Universidade Federal de Lavras, Lavras, Minas Gerais, Brazil. March 24.
  • Type: Conference Papers and Presentations Status: Other Year Published: 2015 Citation: Shock, C.C., E.B.G. Feibert, J.M. Pinto, A. Rivera, and L.D. Saunders. 2015. Onion irrigation management to optimize marketable yield and minimize defects. Universidade Federal de Lavras, Lavras, Minas Gerais, Brazil. March 24.
  • Type: Conference Papers and Presentations Status: Other Year Published: 2015 Citation: Shock, C.C. 2015. Implications of Food Safely Modernization Act. California Garlic and Onion Symposium, 2015. University of California Cooperative Extension & California Garlic and Onion Research Advisory Board, UC Cooperative Extension, Tulare County, Tulare, CA. February 9.
  • Type: Conference Papers and Presentations Status: Other Year Published: 2015 Citation: Reitz, S. 2015. Can we get off the pesticide treadmill for managing onion thrips and Iris Yellow Spot Virus? X International Symposium on Thysanoptera and Tospoviruses, Pacific Grove, CA. http://ucanr.edu/sites/ISTT10/files/199026.pdf.
  • Type: Conference Papers and Presentations Status: Other Year Published: 2015 Citation: Reitz, S.R., R.A. Roncarati, C.C. Shock, H. Kreeft, and J. Klauzer. 2015. Chlorine dioxide injection through drip irrigation reduces Escherichia coli. 2015 ASABE/IA Irrigation Symposium. International Irrigation Show, Long Beach, CA. November 11.


Progress 10/01/13 to 09/30/14

Outputs
Target Audience: Onion growers and shippers. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Undergraduate students and newly graduated students were trained in research protocols and learned about onion management and disease. How have the results been disseminated to communities of interest? The Oregon project has continued to effectively transfer information pertinent to IYSV and thrips biology to growers, other onion industry parties, and the public through numerous meetings, field days, workshops, publications, and the internet. Results have been effectively communicated by grower and fieldman participation in the project planning and evaluation of results, field days for growers July 9, 2014 and August 26, 2014, an irrigation workshop on December 18, 2014, a pesticide short course, grower meetings on February 4, 2014, internet web sites (cropinfo.net), and results being reported in Onion World and other industry publications, such as the Capital Press. What do you plan to do during the next reporting period to accomplish the goals? We plan to continue the same activities reported above in our accomplishments of goals.

Impacts
What was accomplished under these goals? 1. Evaluate onion germplasm for greater levels of tolerance to Iris yellow spot virus (IYSV), other pathogens and thrips. (C. Shock, E. Feibert, A. Rivera, and M. Saunders) Early maturity and full season onion variety trials were conducted in 2014 with support of Idaho-Eastern Oregon Onion Committee and various seed companies. The full season varieties were grown under both furrow and drip irrigation. All varieties were evaluated for their yield, maturity and susceptibility to thrips damage and IYSV. Varieties had significant differences in IYSV severity in 2014. 2. Investigate thrips biology and IYSV epidemiology to improve management strategies. Oregon (S. Reitz, C. Shock, E. Feibert, and M. Saunders) - Two insecticide rotation trials were conducted to evaluate the effectiveness of various insecticides in managing thrips and IYSV. One trial included all foliar applied treatments and the other featured insecticides applied through drip irrigation and by ground. Thrips populations and onion bulb yield varied significantly between treatments, suggesting that thrips and IYSV are significant limiting factors for onion production. Movento and Agri-mek were effective in early season thrips management. The timing of Movento applications is critical so that sufficient levels are in the plant before large thrips populations have developed. Radiant remains the most effective insecticide for mid to late season thrips management. Other materials (e.g., Aza-direct and M-Pede tank mixes) do not always reduce thrips abundance but do contribute to higher yields. Drip applied products did not outperform foliar applied products, but these applications may reduce grower expenses but reducing overall application costs. Insecticide susceptibility trials were conducted by collecting onion thrips from commercial fields throughout the area and exposing them to one of four commonly used insecticides (Agri-mek, Lannate, Movento, Radiant), and demonstrate that populations remain susceptible to these chemicals. 3. Investigate the biology, ecology and epidemiology of other pathogens to improve management strategies. Oregon (S. Reitz, C. Shock, R. Roncarati, E. Feibert, A. Rivera, and M. Saunders). The United States Food and Drug Administration (FDA) has proposed draft rules to implement the Food Safety Modernization Act (FSMA). As part of FSMA, the FDA has proposed that plastic totes be substituted for wooden bins for the storage of onion bulbs as a means to reduce the risk of contamination of onions with potential human pathogens. A replicated study was conducted in 2014 to compare the roles of wooden and plastic storage containers on contamination of onion bulbs with Escherichia coli. E. coli levels of onions grown in five replicated furrow-irrigated plots using water containing 55.4 to greater than 2420 MPN (most probable number) E. coli /100 ml and harvested into old wooden boxes and sterilized plastic crates were compared with E. coli levels of onions grown in five replicated drip-irrigated plots using water with 0 MPN E. coli /100 ml and harvested into similar containers. Onions were prepared for shipment (packed out) through removal of loose skin, roots and soil. The onions tended to not have E. coli on the bulb exteriors or interiors, regardless of storage container. Considering onions from both 2013 and 2014, traces of E. coli on a few of the onion exteriors were not related to the storage containers or irrigation water source, as these traces in exterior samples were found in association with onions grown with both types of irrigation and stored in both types of containers. Surface irrigation systems reusing water may deliver bacteria to produce destined for fresh consumption. We tested the potential for furrow irrigation using canal water with moderate or high levels of E. coli contamination and drip irrigation using canal water and well water free of E. coli to deliver E. coli to onion bulbs. The four irrigation systems (replicated five times) applied water to onion on silt loam. Water was sampled hourly for E. coli and the lateral movement of E. coli in the soil solution was tracked by soil samples and Sterile Soil Solution Samplers at the end of irrigations. Onions were sampled for E. coli contamination. Furrow irrigation delivered E. coli to the soil immediately adjacent to the onion bulbs. E. coli movement under drip irrigation was mostly confined to near the drip tape and very little reached the onion bulbs, indicating that drip irrigation does not directly deliver E. coli to onions. The project started as a way to address the Food safety Modernization Act (FSMA) agricultural water quality rules. The FDA published proposed revisions to the rules at the end of September 2014. Because we will not know what the final rules are until late in 2015, we felt it was important to continue with research on ways to reduce E. coli levels in case that would be needed under the final rules. Although the final FSMA rules have not been published, we wished to determine if certain crop management and maintenance methods growers already use could be adapted for managing E. coli. The three different options for managing E. coli that we examined were: Chlorine dioxide in drip irrigation systems. Injections of chlorine dioxide are used to control the growth of algae in drip irrigation lines. We found that current rates of chlorine dioxide virtually eliminated E. coli. Lower rates also significantly reduce E. coli levels far below proposed FDA standards of 126 CFU / 100 ml. Copper sulfate added to irrigation ditches. Copper sulfate can also be used to help control algae growing in irrigation ditches. We found that copper sulfate almost completely eliminates E. coli (we measured E. coli at several points along the irrigation ditch and at the end of furrows in a field). Copper based fungicides and bactericides are used to manage onion diseases and improve onion storage quality. We examined the use of a late season application of a copper based fungicide to treat E. coli that may be on the onion bulbs in the field. We could not judge the effectiveness of this treatment because onions had no E. coli before the treatment was made, suggesting that onions are not likely to acquire E. coli. 4. Facilitate interaction and information transfer between W2008 participants, the onion industry and other stakeholders. Oregon (S. Reitz, C. Shock, E. Feibert, and M. Saunders) - The Oregon project has continued to effectively transfer information pertinent to IYSV and thrips biology to growers, other onion industry parties, and the public through numerous meetings, field days, workshops, publications, and the internet. Results have been effectively communicated by grower and fieldman participation in the project planning and evaluation of results, field days for growers July 9, 2014 and August 26, 2014, an irrigation workshop on December 18, 2014, a pesticide short course, grower meetings on February 4, 2014, internet web sites (cropinfo.net), and results being reported in Onion World and other industry publications, such as the Capital Press.

Publications

  • Type: Journal Articles Status: Published Year Published: 2014 Citation: Reitz, S. R. 2014. Onion thrips (Thysanoptera: Thripidae) and their management in the Treasure Valley of the Pacific Northwest. Florida Entomologist, 97: 349-354.
  • Type: Other Status: Published Year Published: 2014 Citation: Shock, C.C., E.B.G. Feibert, and L.D. Saunders. 2014. 2013 Onion variety trials. p 10-28 In Shock C.C. (Ed.) Oregon State University Agricultural Experiment Station, Malheur Experiment Station Annual Report 2013, Department of Crop and Soil Science Ext/CrS 149.
  • Type: Other Status: Published Year Published: 2014 Citation: Shock, C.C., E.B.G. Feibert, and L.D. Saunders. 2014. Onion production from transplants. p 29-33 In Shock C.C. (Ed.) Oregon State University Agricultural Experiment Station, Malheur Experiment Station Annual Report 2013, Department of Crop and Soil Science Ext/CrS 149.
  • Type: Other Status: Published Year Published: 2014 Citation: Pinto, J.M., C.C. Shock, E.B.G. Feibert, and L.D. Saunders. 2014. Onion response to irrigation criteria for two varieties at two plant populations. p 34-36 In Shock C.C. (Ed.) Oregon State University Agricultural Experiment Station, Malheur Experiment Station Annual Report 2013, Department of Crop and Soil Science Ext/CrS 149.
  • Type: Other Status: Published Year Published: 2014 Citation: Pinto, J.M., C.C. Shock, E.B.G. Feibert, and L.D. Saunders. 2014. Onion response to phosphorus application strategies and in-season nutrient supplementation. p 47-56 In Shock C.C. (Ed.) Oregon State University Agricultural Experiment Station, Malheur Experiment Station Annual Report 2013, Department of Crop and Soil Science Ext/CrS 149.
  • Type: Other Status: Published Year Published: 2014 Citation: Pinto, J.M., C.C. Shock, E.B.G. Feibert, and L.D. Saunders. 2014. Onion response to late-season water stress at two plant populations. p 57-65 In Shock C.C. (Ed.) Oregon State University Agricultural Experiment Station, Malheur Experiment Station Annual Report 2013, Department of Crop and Soil Science Ext/CrS 149.
  • Type: Other Status: Published Year Published: 2014 Citation: Reitz, S., C.C. Shock, E.B.G. Feibert, L.D. Saunders, and E. Jemmett. 2014. Evaluation of insecticides and insecticide use patterns for management of thrips and Iris Yellow Spot Virus. p 66-79 In Shock C.C. (Ed.) Oregon State University Agricultural Experiment Station, Malheur Experiment Station Annual Report 2013, Department of Crop and Soil Science Ext/CrS 149.
  • Type: Other Status: Published Year Published: 2014 Citation: Reitz, S., C.C. Shock, E.B.G. Feibert, L.D. Saunders, and E. Jemmett. 2014. New fungicide treatments for disease management and plant health in onions. p 80-87 In Shock C.C. (Ed.) Oregon State University Agricultural Experiment Station, Malheur Experiment Station Annual Report 2013, Department of Crop and Soil Science Ext/CrS 149.
  • Type: Other Status: Published Year Published: 2014 Citation: Reitz, S., C.C. Shock, E.B.G. Feibert, and L.D. Saunders. 2014. Bed type and soil fumigant effects on yield, quality, and pink root incidence and severity in onions in the Treasure Valley. p 88-101 In Shock C.C. (Ed.) Oregon State University Agricultural Experiment Station, Malheur Experiment Station Annual Report 2013, Department of Crop and Soil Science Ext/CrS 149.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2013 Citation: Shock, C.C., E.B.G. Feibert, and J.M. Pinto. 2013. Review of two decades of progress in the development of successful drip irrigation for onions. International Irrigation Show, November 5-7, Austin, TX.
  • Type: Conference Papers and Presentations Status: Other Year Published: 2013 Citation: Shock, C.C. and B.M. Shock. 2013. Preliminary Results, E. coli and Onions. Multi-State Project, W2008: Biology and Management of Iris Yellow Spot Virus (IYSV), Other Diseases, and Thrips in Onions, Denver, CO, December 12.
  • Type: Conference Papers and Presentations Status: Other Year Published: 2013 Citation: C. Shock, J.M. Pinto, H. Kreeft, R. Ross, T. Laubacher and B. Shock. 2013. E. coli and Onions. Treasure Valley Irrigation Conference, Four Rivers Cultural Center, Ontario, OR, 17 December.
  • Type: Conference Papers and Presentations Status: Other Year Published: 2013 Citation: Reitz, S.R. 2013. Onion thrips biology and management. Pacific Northwest Vegetable Association, Kennewick, WA, 13 November.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2014 Citation: Shock, C.C., J.M. Pinto, H. Kreeft, and B.M. Shock. 2014. Survival of E. coli on onions during curing. American Society of Horticultural Science annual meeting, Orlando, FL, 28 July.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2014 Citation: Shock, B.M. and C.C. Shock. 2014. Surface irrigation systems that deliver bacteria to vegetable crops. American Society of Horticultural Science annual meeting, Orlando, FL, 28 July.


Progress 10/01/12 to 09/30/13

Outputs
Target Audience: Onion growers and shippers Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Two undergraduate students learned about onion research and helped write reports. How have the results been disseminated to communities of interest? Findings from this research has been posted on websites, published in newsletters, presented at various meetings, and communicated directly with growers and other industry personnel. This information has led to the adoption of more effective management programs in onion cropping systems. 1. More growers are adopting onion varieties with greater tolerance to IYSV. 2. More growers are adopting drip irrigation and maintaining better management of soil moisture. The onions grown with drip irrigation and careful irrigation scheduling tended to have less severe problems with IYSV. 3. Growers continue to improve their use of insecticide rotation programs through the growing season. Research trials have led to the identification of effective season-long insecticide use programs. These programs have enabled growers to successfully manage thrips over a single growing season and reduce the risk of insecticide resistance developing. 4. Due to better knowledge of the transmission of IYSV, fewer growers are planting over-wintering onions. With fewer overwintering onions and better cull onion disposal, growers are breaking the natural green bridge keeping IYSV pressure high from one production year to the next. Some growers continued to suffer IYSV related yield losses due to over-wintering onion bulb or seed fields close to their summer production fields. What do you plan to do during the next reporting period to accomplish the goals? We plan to continue the same activities reported above in our accomplishment of goals.

Impacts
What was accomplished under these goals? 1. Evaluate onion germplasm for greater levels of tolerance to Iris yellow spot virus (IYSV), other pathogens and thrips In 2013 four early-season yellow varieties were planted in March and were harvested and graded in mid-August. Forty-nine full-season varieties (49 yellow, 3 red, and 7 white) were planted in March, harvested in September 2013, and graded out of storage in January 2014. Onions in each plot of the full-season trial were evaluated for maturity and for severity of symptoms of iris yellow spot virus (IYSV). Each plot was given a subjective rating on a scale of 0 to 5 of increasing severity of IYSV symptoms. During grading, bulbs were be separated according to quality: bulbs without blemishes (No. 1s), split bulbs (No. 2s), neck rot (bulbs infected with the fungus Botrytis allii in the neck or side), plate rot (bulbs infected with the fungus Fusarium oxysporum), and black mold (bulbs infected with the fungus Aspergillus niger). Varieties varied in botrytis, plate rot, black mold, but not IYSV which was very low in field trials in 2013. 2. Investigate thrips biology and IYSV epidemiology to improve management strategies A field trial testing 20 insecticide regimes was established in 2013. Insecticides were applied to the foliage weekly for 8 weeks from late-May through mid-July. Thrips were monitored by counting thrips on 15 plants per plot. Plants were subjectively rated for thrips feeding damage and severity of IYSV infection. Onions were harvested and graded to determine yield. Thrips pressure was high throughout the season but there were significant differences among the insecticide regimes in terms of thrips and IYSV management and yield. Yield was significantly related to onion thrips pressure, with programs that maintained the best management of thrips during the middle of the season (late June-early July) tending to have the highest yields and greater proportions of colossal and supercolossal sized onions. A program to monitor for insecticide resistance in onion thrips was started in 2013. Feral thrips were collected from commercial fields and then exposed to insecticide treated onion foliage under laboratory conditions. Mortality was assessed after 24 and 48 hours of exposure. Results indicate that onion thrips populations remain highly susceptible to four commonly used insecticides, Agri-Mek, Movento, Lannate and Radiant. 3. Investigate the biology, ecology and epidemiology of other pathogens to improve management strategies Studies were initiated to understand the movement of E. coli in water and soil and E. coli survival on onion bulbs. Onions of all treatments of all experiments discussed above were evaluated for plate rot, botrytis, and black mold. 4. Facilitate interaction and information transfer between W2008 participants, the onion industry and other stakeholders. The project has continued to effectively transfer information pertinent to IYSV and thrips biology to growers, other onion industry parties, and the public through numerous meetings, field days, publications, and the internet. Results have been effectively communicated by grower and fieldman participation in the project planning and evaluation of results, field days for growers July 10, 2013 and August 26, 2013, tour for the FDA August 12, 2013, grower meetings on February 5, 2013, internet web sites, and results being reported in Onion World and the Capitol Press.

Publications

  • Type: Conference Papers and Presentations Status: Other Year Published: 2013 Citation: Reitz, S.R. 2013. Lessons learned from a distant land: Onion thrips and their management in the Pacific Northwest. Symposium on Thrips  Small Players with Big Damages, Annual Meeting of Florida Entomological Society, Naples, FL, 17 July.
  • Type: Conference Papers and Presentations Status: Other Year Published: 2013 Citation: Shock, C.C., E.B.G. Feibert, L.D. Saunders. 2013. Onion variety response to plant population and irrigation system. Annual Conference of the American Society of Horticultural Science, Palm Desert, CA, 25 July.
  • Type: Conference Papers and Presentations Status: Other Year Published: 2012 Citation: Reitz*, S., C.C. Shock, E.B.G. Feibert, E. Jemmett, and L.D. Saunders, Insecticide rotations for control of thrips in onion. National Allium Research Conference 2012, Hotel Encanto de Las Cruces, December 12-13, Las Cruces, NM.
  • Type: Conference Papers and Presentations Status: Other Year Published: 2012 Citation: Shock*, C.C., E.B.G. Feibert, and S. Reitz. 2012. Oregon 2012 update on IYSV and thrips, Multi-State Project, W2008: Biology and Management of Iris Yellow Spot Virus (IYSV), Other Diseases, and Thrips in Onions, December 14.
  • Type: Conference Papers and Presentations Status: Other Year Published: 2013 Citation: Shock, C.C. E.B.G. Feibert, and L.D. Saunders. 2013. Plant population options for marketing long-day onions. Idaho and Malheur County Onion Growers Associations  53rd Annual Meeting, Four Rivers Cultural Center, Ontario, OR, 5 February.
  • Type: Conference Papers and Presentations Status: Other Year Published: 2013 Citation: Shock, C.C. E.B.G. Feibert, L.D. Saunders, E. Jemmett, and S. Reitz. 2013. Alternative Methods for Thrips Control in Onions, 2012. Idaho and Malheur County Onion Growers Associations  53rd Annual Meeting, Four Rivers Cultural Center, Ontario, OR, 5 February.
  • Type: Conference Papers and Presentations Status: Other Year Published: 2013 Citation: Shock, C.C., S. Reitz, and E.B.G. Feibert. 2013. Onion production tour including thrips control, iris yellow spot virus, fertigation, irrigation, onions grown from sets and transplants, irrigation management and soil moisture monitoring. Summer Farm Festival and Field Day, Oregon State University Malheur Experiment Station, Ontario, OR, 10 July.
  • Type: Conference Papers and Presentations Status: Other Year Published: 2013 Citation: Shock, C.C. 2013. Food and Drug Administration Tour of Onion Production, Ontario, OR, 12 August.
  • Type: Other Status: Published Year Published: 2013 Citation: Shock, C.C., J.M. Pinto, T.A. Laubacher, R.D. Ross, A.C. Mahony, H. Kreeft, and B.M. Shock, 2013. Movement of Escherichia coli is soil as applied in irrigation water. In Shock, C.C. Ed. Preliminary studies on Shock, C.C., J.M. Pinto, T.A. Laubacher, R.D. Ross, A.C. Mahony, H. Kreeft, and B.M. Shock, 2013. Movement of Escherichia coli is soil as applied in irrigation water. In Shock, C.C. Ed. Preliminary studies on Escherichia coli and onion. Oregon State University Malheur Experiment Station, Department of Crop and Soil Science Special Report, Ext/CrS 148: 1-17. Shock, C.C., J.M. Pinto, T.A. Laubacher, R.D. Ross, A.C. Mahony, H. Kreeft, and B.M. Shock, 2013. Survival of Escherichia coli on onion during field curing and packout. In Shock, C.C. Ed. Preliminary studies on Escherichia coli and onion. Oregon State University Malheur Experiment Station, Department of Crop and Soil Science Special Report, Ext/CrS 148: 18-27. Shock, C.C., J.M. Pinto, H. Kreeft, and B.M. Shock, 2013. Onion storage in sterilized new plastic crates compared to storage in old wooden boxes. In Shock, C.C. Ed. Preliminary studies on Escherichia coli and onion. Oregon State University Malheur Experiment Station, Department of Crop and Soil Science Special Report, Ext/CrS 148: 28-35. Ross, R.D., C.C. Shock, T.A. Laubacher, J.M. Pinto, A.C. Mahony, H. Kreeft, and B.M. Shock, 2013. Simulated filtration pond to remove Escherichia coli from irrigation water. In Shock, C.C. Ed. Preliminary studies on Escherichia coli and onion. Oregon State University Malheur Experiment Station, Department of Crop and Soil Science Special Report, Ext/CrS 148: 36-43.
  • Type: Other Status: Published Year Published: 2013 Citation: Shock, C.C., E.B.G. Feibert, and L.D. Saunders. 2013. 2012 Onion variety trials. p 12-25 In Shock C.C. (Ed.) Oregon State University Agricultural Experiment Station, Malheur Experiment Station Annual Report 2012, Department of Crop and Soil Science Ext/CrS 144. Shock, C.C., E.B.G. Feibert, and L.D. Saunders. 2013. Onion production from transplants and sets. p 26-34 In Shock C.C. (Ed.) Oregon State University Agricultural Experiment Station, Malheur Experiment Station Annual Report 2012, Department of Crop and Soil Science Ext/CrS 144. Shock, C.C., E.B.G. Feibert, and L.D. Saunders. 2013. Onion variety response to plant population and irrigation system. p 35-62 In Shock C.C. (Ed.) Oregon State University Agricultural Experiment Station, Malheur Experiment Station Annual Report 2012, Department of Crop and Soil Science Ext/CrS 144. Shock, C.C., E.B.G. Feibert, K.J. Barlow, A.L. Rock, L.D. Saunders, E. Jemmett, and S. Reitz. 2013. Insecticide rotations for thrips control in onions, 2012. p 63-69 In Shock C.C. (Ed.) Oregon State University Agricultural Experiment Station, Malheur Experiment Station Annual Report 2012, Department of Crop and Soil Science Ext/CrS 144. Shock, C.C., E.B.G. Feibert, K.J. Barlow, A.L. Rock, L.D. Saunders, E. Jemmett, and S. Reitz. 2013. Alternative methods for thrips control in onions, 2012. p 70-75 In Shock C.C. (Ed.) Oregon State University Agricultural Experiment Station, Malheur Experiment Station Annual Report 2012, Department of Crop and Soil Science Ext/CrS 144.
  • Type: Other Status: Published Year Published: 2013 Citation: Shock, C.C., F.X. Wang, R.J. Flock, E.B.G. Feibert, C.A. Shock, and A.B. Pereira. 2013. Irrigation monitoring using soil water tension. Sustainable Agriculture Techniques, Oregon State University Extension Service. EM 8900 10p. http://ir.library.oregonstate.edu/xmlui/bitstream/handle/1957/37569/em8900.pdf Shock, C.C. T. Welch, F.X. Wang R. Flock, E.B.G. Feibert, C.A. Shock, y A.B. Pereira. 2013. El control del riego mediante la tensi�n matricial del suelo. Tecnicas para la agricultura sostenible, Oregon State University Extension Service, Corvallis. EM 8900-S-E. 10p. http://ir.library.oregonstate.edu/xmlui/bitstream/handle/1957/37648/em8900-s.pdf Shock, C.C. 2013. Drip Irrigation: An Introduction. Sustainable Agriculture Techniques, Oregon State University Extension Service, Corvallis. EM 8782-E 8p. http://ir.library.oregonstate.edu/xmlui/bitstream/handle/1957/37461/em8782.pdf C.C. Shock y T. Welch. 2013. El riego por goteo: Una introducci�n. Tecnicas para la agricultura sostenible, Oregon State University Extension Service, Corvallis. EM 8782-S 9p. http://ir.library.oregonstate.edu/xmlui/bitstream/handle/1957/37462/em8782-S.pdf Shock, C.C., R.J. Flock, E.B.G. Feibert, C.A. Shock, and J. Klauzer. 2013. Drip irrigation guide for onion growers in the Treasure Valley. Sustainable Agriculture Techniques, Oregon State University Extension Service. EM 8901 8p. http://ir.library.oregonstate.edu/xmlui/bitstream/handle/1957/43725/em8901.pdf Shock, C.C., B.M. Shock, and T. Welch. 2013. Strategies for efficient irrigation water use. Sustainable Agriculture Techniques, Oregon State University Extension Service. EM8783. 7p. http://ir.library.oregonstate.edu/xmlui/bitstream/handle/1957/37465/em8783.pdf