GUIDING DISEASE MANAGEMENT OF SMALL FRUIT CROPS TOWARDS A SUSTAINABLE FUTURE.

• Sponsoring Institution: National Institute of Food and Agriculture
• Project Status: TERMINATED
• Funding Source: HATCH
• Reporting Frequency: Annual
• Accession No.: 1008899
• Project No.: MICL02424
• Project Start Date: Mar 1, 2016
• Project End Date: Oct 31, 2018

Project Director
Schilder, AN.

Recipient Organization
MICHIGAN STATE UNIV
(N/A)
EAST LANSING,MI 48824

Performing Department
Plant, Soil and Microbial Science

Non Technical Summary
Small fruit crops greatly contribute to Michigan's agricultural diversity and economy. Michigan is among the top blueberry-producing states in the US with over 20,000 acres in production, yielding 99 million pounds valued at $123 million in 2014. Grapes for juice and wine are produced on a total of about 14,000 acres, with wine grape acreage at 3,000 acres and steadily expanding. The total amount of grapes produced in 2014 was 63,000 tons valued at over $19 million. Strawberries are produced on about 850 acres, raspberries on 600 acres, and cranberries on 500 acres with a total production value of about $10 million. Both strawberries and raspberries are important in supplying local fresh fruit and pick-your-own markets, whereas cranberries may be shipped fresh or frozen. Other small fruits, such as gooseberries, currants, saskatoonberries, elderberries and hardy kiwis are grown on a small scale, mostly for the fresh market or home use. In recent years, there has been a trend towards more organic or sustainable fruit production as well as an expansion to non-traditional fruit-growing areas with the availability of cold-hardy grape and other fruit. The combined value of small fruit crops in Michigan exceeds 155 million dollars per year. Small fruit crops are usually grown in perennial systems and in the humid Midwestern climate are affected by a variety of fungal diseases which can significantly reduce fruit yield and quality as well as longevity of the plantings. The initial investment into a planting may be high due to the installation of trellising and irrigation systems and economic returns can only be expected after multiple years due to slow establishment of the crop. High disease pressure and strict standards for fruit quality (including a zero tolerance for some diseases, e.g., mummy berry) imposed by marketers and processors, lead to heavy reliance on synthetic chemicals for disease control. Multiple fungicide applications per season are common, with grapes receiving up to twelve, blueberries up to eight, and strawberries and brambles up to six or seven fungicide sprays per season. Increased mechanization of pruning and harvesting may contribute to disease development by leaving more diseased plant material in the field, and causing wounds which provide entry ways for pathogens into the plants. Virus diseases have also become more important in recent years and demonstrate the continued need for virus-free planting material, which is facilitated and promoted by the National Clean Plant Network (http://nationalcleanplantnetwork.org/). Most small fruit growers take an integrated approach to disease management. Efficacious alternatives to conventional fungicides may not always be available or (cost-)effective. Some of the most affordable broad-spectrum fungicides, mancozeb and captan, are suspected carcinogens and their use is restricted by some fruit processors. Sterol inhibitors, a fungicide group that forms the backbone of many fruit disease management programs in Michigan (Wise et al., 2014), are believed to have endocrine effects (Taxvig et al., 2007). Many of the new fungicide groups, such as the succinate dehydrogenase inhibitors (SDHI's), are prone to resistance development in target pathogens (FRAC. In addition, the proximity of much of the fruit production areas in Michigan and light sandy soils put Lake Michigan watersheds at risk of chemicals which, through leaching, may end up in ground or surface water. Integrated disease management is critical in safeguarding environmental quality and economic prosperity while maintaining fruit quality. To promote additional disease control options, genetic, cultural, and biological control methods need to be further investigated. Over the past 10-15 years, interest in organic fruit production has increased among small fruit growers in Michigan but overall, the organic small fruit acreage remains small (<1%) mostly due to pest management concerns. Covered production of fruit in tunnels is increasing, changing the spectrum of diseases in such systems. The number of biocontrol and "soft" fungicides on the market has increased greatly in recent years but efficacy data are limited due to the minimal requirements of EPA for efficacy data in the registration process. It is important that we understand the spectrum and limitations of these fungicides before putting growers' crops and livelihoods at risk. The overall goal of this project is to increase the environmental and economic sustainability of fruit production by improving the cost-effectiveness of disease management programs while assisting growers in producing high-quality fruit. To achieve this, a better understanding of the biology of major fruit pathogens is needed to optimize existing disease control methods. Alternatives to current chemical fungicides, such as the use of cultivar resistance, and cultural and biological control methods need to be further explored. The integration of the most effective disease control options and the utility of disease scouting and forecasting need further investigation as well. The broad objectives of the project are to: 1) Improve diagnosis of diseases and assessment of losses on small fruit crops, 2) Elucidate the biology and population characteristics of small fruit pathogens, 3) Study the effects of environmental factors and fungicides on small fruit pathogens, and 4) Evaluate the efficacy of integrated disease management methods. The results are expected to increase short-term profitability and long-term sustainability of the small fruit production and processing industries in Michigan by reducing production costs and environmental exposure associated with fungicide applications and increasing income due to improved yield and quality of fruit. Non-synthetic chemical alternatives for disease control can also enlarge the scope for IPM-based and organic production of small fruit crops, providing added value and potential new marketing niches. Alternative disease control methods are expected to reduce environmental contamination by pesticides and improve food and worker safety, which should benefit growers and consumers alike. At a time when food safety is becoming a major international issue, improving the image of fruit production in Michigan will be beneficial for the agricultural sector as a whole.

Animal Health Component

0%

Research Effort Categories

Basic

15%

Applied

80%

Developmental

5%

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
212	1199	1102	80%
212	1199	1101	20%

Knowledge Area
212 - Pathogens and Nematodes Affecting Plants;

Subject Of Investigation
1199 - Deciduous and small fruits, general/other;

Field Of Science
1101 - Virology; 1102 - Mycology;

Keywords

grapes

blueberries

strawberries

raspberries

plant pathogen

fungus

virus

fungicide resistance

organic

clean plants

Goals / Objectives
The project aims to enhance environmental and economic sustainability of small fruit crops by diversifying disease control options while improving fruit quantity and quality. To achieve this, a better understanding of the biology of major fruit pathogens is needed to optimize existing disease control methods. Alternatives to current chemical fungicides, such as the use of cultivar resistance, and cultural and biological control methods need to be further explored. The integration of the most effective disease control options and the utility of disease scouting and forecasting need further investigation as well. The broad objectives of the project are to:1) Improve diagnosis of diseases and assessment of losses on small fruit crops2) Elucidate the biology and population characteristics of small fruit pathogens3) Study the effects of environmental factors and fungicides on small fruit pathogens4) Evaluate the efficacy of integrated disease management methods

Project Methods
1) Improve diagnosis of diseases and assessment of losses on small fruit crops in Michigana) Diagnose diseases in small fruit crops in MichiganWe will continue to provide diagnostic support for diseases on small fruit crops, using culture and spore morphology, DNA sequencing, and other methods to identify potential pathogens. We will confirm pathogenicity by doing Koch's postulates. Surveys will also be conducted in grapes, blueberries and raspberries to assess the prevalence of virus and virus-like diseases.b) Disease-loss relationships for small fruit diseasesWe will continue to investigate the effects of specific diseases and timing of disease onset on plant growth, yield and fruit quality. The main goal is to develop economic thresholds to help guide growers with disease management decisions. We will continue experiments to determine the impact of Phomopsis twig blight on yield components in blueberry. This will be done by simulating different levels of loss of flower clusters at full bloom in Bluecrop, Jersey and Elliott in a replicated field trial. Berries will be harvested at maturity, weighed and counted. The percent yield loss in relation to the number of clusters removed will be determined by regression analysis.2) Elucidate the biology and population characteristics of small fruit pathogensa) Characterize pathogen populations in small fruit crops in MichiganColletotrichum, Phomopsis, and Monilinia vaccinii-corymbosi isolates collected from blueberries and other small fruit crops in Michigan will be used for this study. DNA from the internal transcribed spacer (ITS) region and other genes will be sequenced to identify them to the correct species. Phylogenetic analysis will be done to study population diversity and relatedness of isolates. We will also evaluate culture morphology, virulence on susceptible plant tissues, and fungicide sensitivity to commonly used fungicides. Data will be analyzed using sequence analysis and phylogenetic computer programs as well as mixed model followed by mean separation in SAS.b) Study the biology of grape downy mildew strains in MichiganWe will study the biology of the different cryptic species of downy mildew on grapes in Michigan, which may differ in environmental requirements for infection and spread. We will compare various spore traps and specific PCR primers to monitor spore release in the field. We will also use trap plants to determine infectivity of the spores. Specific leaf wetness and temperature requirements for infection will be studied on leaf disks and potted plants. Data will be analyzed using mixed model analysis followed by mean separation in SAS.3) Study the effects of environmental factors and fungicides on small fruit pathogensa) Develop disease prediction models for anthracnose fruit rot and mummy berry in blueberryWe will continue to develop, refine and validate infection prediction models for anthracnose fruit rot and mummy berry in blueberry. In addition, a model for spore release will be developed. We are in the process of validating primary infection requirements for mummy berry in highbush blueberry based on leaf wetness and temperature work done in low-bush blueberry. Data will be analyzed using regression analysis as well a mixed model analysis in SAS.b) Validate disease prediction models for powdery mildew, downy mildew, and Phomopsis in grapesWe will validate mechanistic disease prediction models for primary infection of powdery and downy mildew in grapes developed by Dr. Vittorio Rossi in Piacenza, Italy. This will be done by visually scouting unsprayed sentinel and other vineyards for the onset of disease signs and symptoms and comparing the dates to the output from the models. In addition, infection and spore release models developed for Phomopsis cane and leaf spot at Ohio State University will be programmed into EnviroWeather and validated by observing symptom development and quantifying spores in spore traps in Michigan vineyards. Data will be analyzed using regression analysis as well a mixed model analysis in SAS.c) Protective and curative activity and retention of fungicides in blueberries and grapesPre- and post-infection activity of fungicides will be assessed against C. acutatum on blueberries and Phomopsis viticola on grapes in order to improve recommendation on fungicide timing. Fungicides (e.g., Pristine, Quash/Procure, Captan/Ziram) will be applied at different times before and after inoculation. Disease severity and incidence will be assessed visually. We will assess the rainfastness of fungicides on grape and blueberry leaves and fruit in the field by quantifying fungicide residues and disease severity after different amounts of rainfall in order to develop fungicide "decay" models to be incorporated in EnviroWeather. Data will be analyzed using Mixed Model analysis followed by mean separation in SAS.4) Evaluate the efficacy of integrated disease management methodsa) Identify sources and nature of resistance to diseases in small fruit cropsThe blueberry variety plantings in Fennville will be used to evaluate resistance to leaf rust and resistance of blueberry cultivars and grape rootstocks to nepoviruses (TRSV and ToRSV) will be studied in a new planting in a field with a disease history. Plants in the latter study will be observed for 3-5 years to allow for natural infection by dagger nematodes and disease expression. As funding allows, we will continue to study the function of specific resistance genes to C. acutatum in blueberry through virus-induced gene silencing (VIGS) and transformation of early-flowering blueberry plants in collaboration with Paul Goodwin and Guo-Qing Song.b) Effect of different plastics on disease management in tunnel-grown raspberries and strawberriesWe will continue to work with Eric Hanson and PIs at Penn State University on a SCRI-funded project to determine the effects of different plastics and plant densities on disease incidence and severity and fungicide residue breakdown in tunnel-grown raspberries and strawberries. In addition, we will evaluate the efficacy of biological control agents against powdery mildew and late leaf rust, which tend to be more prevalent in tunnels. Work will be done under natural infection conditions. Data will be analyzed using Mixed Model analysis followed by mean separation in SAS.c) Effect of cultural practices on disease pressure and overwintering inoculumDifferent sanitation methods, such as leaf and cane removal and methods to speed up decomposition of plant debris will be evaluated for inoculum reduction in grapes and blueberries. Replicated trials will be done in commercial and experimental fields with a history of disease. In addition, a multi-year trial is ongoing in the "vineyard of the future" with an 8-ft trellis and different training systems in collaboration with Tom Zabadal, Paolo Sabbatini and Rufus Isaacs. We will assess the effect of the treatments on severity of foliar and fruit diseases. In addition, we will evaluate soil treatments incl. the use of nematode-suppressive cover crops, anaerobic soil disinfestation, and biofumigation with brassicaceous crops for efficacy nematodes and soilborne. Data will be analyzed using Mixed Model analysis followed by mean separation in SAS.d) Efficacy of reduced-risk and biological fungicides and compost teas against small fruit diseasesNew and reduced-risk fungicides and biological control products will be evaluated for their efficacy in controlling foliar and fruit diseases of small fruit crops. Products will be applied during the growing season and disease evaluation will be by visual assessment. We will continue to do experiments on compost teas to determine the active components that increase disease suppressiveness. Data will be analyzed using Mixed Model analysis followed by mean separation in SAS.

Progress 03/01/16 to 10/31/18

Outputs
Target Audience:The primary target audience for the project was small fruit growers, nursery owners, extension personnel and private consultants in Michigan and the Great Lakes region. in addition, the project reached small fruit growers and other stakeholders throughout the United states and the world. Furthermore, undergraduate and graduate students were educated in small fruit disease diagnosis and management as part of this project. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?The project provided training opportunities for one graduate student (Master's degree) and four undergraduate students in research and analysis techniques. A technician received training in Real-Time Polymerase Chain Reaction techniques at the Foundation Plant Services facility at University of California-Davis. How have the results been disseminated to communities of interest?Results have been disseminated to communities of interest via oral and poster presentations at extension and scientific meetings, extension newsletters and grower meetings. Information has also been disseminated verbally directly to growers and consultants, in the form of disease diagnosis and disease management recommendations. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? Improve diagnosis of diseases and assessment of losses on small fruit crops During late summer of 2016, 438 composite grape leaf samples were taken from over 100 wine grape vineyards in mid, southwest and northwest Michigan representing 55 different growers. In most cases, each vineyard was represented by four samples from four randomly selected rows. Testing was conducted on each sample using real-time polymerase chain reaction (RT-PCR) at the Foundation Plant Services facility on the UC Davis campus. Each sample was tested for 28 different viral or phytoplasma pathogens. A large number of samples (85%) tested positive for Grape rupestris stem pitting virus (GRSPaV). Other commonly found pathogens were Grape leafroll associated virus (GLRaV) 28% (any strain), Grapevine fleck virus (GFkV) 17%, Grapevine virus A (GVA) 11% and Tobacco ringspot virus (TRSV) 12%. In all, only 45 of the 438 samples (10%) were negative for all the tested pathogens. Since growers often attribute virus symptoms to "fall color" or nutrient deficiencies, the results of this survey confirm the results of other preliminary surveys that a high percentage of wine grapevines in Michigan are infected with virus. Reports have been sent to all of the survey participants and the data has been presented at multiple extension conferences. Elucidate the biology and population characteristics of small fruit pathogens No new work has been conducted on this objective. Study the effects of environmental factors and fungicides on small fruit pathogens In support of sustainable agriculture, a field trial was conducted to evaluate the effectiveness of six organic products on their effectiveness at inactivating overwintering inoculum in grapevines. Grape clusters infected with botrytis, cane pieces infected with phomopsis, and grape berries infected with black rot were treated with the six organic agents (in individual treatments). The treated infected plant material was placed in mesh bags, hung in a vineyard, and overwintered. Samples were brought back to the lab in spring of 2018 and are being evaluated to see how well the organic compounds were at inactivating the pathogens. Preliminary results show that the organic agents were not significantly effective at inactivating overwintering inoculum. An additional experiment was conducted to evaluate the effectiveness of removal of leaf litter at reducing powdery mildew and downy mildew infections the following season. Leaves were removed (by hand raking) in large sections of a vineyard in fall of 2017 to remove the potential inoculum. At the end of the next growing season (August 2018) the raked area was rated for disease and compared to areas of the vineyard that were not raked. There was no significant difference in disease levels between the two areas. Evaluate the efficacy of integrated disease management methods Fungicide efficacy trials were conducted for disease control in grapes, blueberries, raspberries and strawberries to evaluate new fungicide products as well as biological control agents and reduced-risk fungicides. Most products and fungicide programs showed good disease control efficacy.

Publications

• Type: Journal Articles Status: Published Year Published: 2016 Citation: J.M. Gillett, A.M.C. Schilder; R.W. Sysak. Evaluating fungicides for control of mummy berry and post-harvest fruit rot in blueberries, 2016. PDMR 12:PF058.
• Type: Journal Articles Status: Published Year Published: 2016 Citation: J.M. Gillett, A.M.C. Schilder; R.W. Sysak. Evaluation of fungicides for control of foliar and fruit diseases of juice grapes, 2016. PDMR 12:PF062.
• Type: Journal Articles Status: Published Year Published: 2016 Citation: J.M. Gillett, A.M.C. Schilder; R.W. Sysak. Evaluation of fungicides for control of leaf and fruit rot diseases in matted-row strawberry, 2016. PDMR 12:PF061.

Progress 10/01/16 to 09/30/17

Outputs
Target Audience:The primary target audience for the project is small fruit growers, nursery owners, extension personnel and private consultants in Michigan and the Great Lakes region. In addition, the project reaches small fruit growers and other stakeholders throughout the United states and the world. Furthermore, undergraduate and graduate students are being educated in small fruit disease diagnosis and management as part of this project. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?The project provided training opportunities for one graduate student (Master's degree) and four undergraduate students in research and analysis techniques. A technician received training in Real-Time Polymerase Chain Reaction techniques at the Foundation Plant Services facility at University of California-Davis. How have the results been disseminated to communities of interest?Results have been disseminated to communities of interest via oral and poster presentations at extension and scientific meetings, extension newsletters and grower meetings.Information has also been disseminated verbally directly to growers and consultants, in the form of disease diagnosis and disease management recommendations. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? Improve diagnosis of diseases and assessment of losses on small fruit crops During late summer of 2016, 438 composite grape leaf samples were taken from over 100 wine grape vineyards in mid, southwest and northwest Michigan representing 55 different growers. . In most cases, each vineyard was represented by four samples from four randomly selected rows. Testing was conducted on each sample using real-time polymerase chain reaction (RT-PCR) at the Foundation Plant Services facility on the UC Davis campus. Each sample was tested for 28 different viral or phytoplasma pathogens. A large number of samples (85%) tested positive for Grape rupestris stem pitting virus (GRSPaV). Other commonly found pathogens were Grape leafroll associated virus (GLRaV) 28% (any strain), Grapevine fleck virus (GFkV) 17%, Grapevine virus A (GVA) 11% and Tobacco ringspot virus (TRSV) 12%. In all, only 45 of the 438 samples (10%) were totally negative for the tested pathogens. Since growers often attribute virus symptoms to "fall color" or nutrient deficiencies, the results of this survey confirm the results of other preliminary surveys that a high percentage of wine grapevines in Michigan are infected with virus. Further studies on the effects of each virus on fruit quality and yield are needed next. 2. Elucidate the biology and population characteristics of small fruit pathogens Symptomatic blueberry canes and twigs were collected form 26 fields (9 total cultivar) showing cane dieback. Fungal isolations were made and sequencing conducted on the ITS regions. Two species of Phomopsis were found: Phomopsis vaccinii and Phomopsis eres. The DNA from each species was amplified for the elongation factor (EF1) and Tubulin (ß-TUB) regions and phylogenetic trees were constructed and confirmed that the two species of Phomopsis were distinct. Experiments to determine if the two species differ in pathogenicity are underway. Other cane pathogens found in the symptomatic tissue included Neofusicoccum spp., Alternaria spp., Pestalotia spp., and Aereobasidium spp. 3. Study the effects of environmental factors and fungicides on small fruit pathogens Rain water spore bottles were placed in three phomopsis infected vineyards that also had a MAWN weather station located nearby. Bottles were changed out every week throughout the growing season of 2017. We are in the process of evaluating how the level of phomopsis spores changes during the season and how that correlates with weather conditions. This data will be used to determine if a phomopsis prediction model from Ohio will work for Michigan conditions. If so, a model will be loaded onto the MAWN website for growers to use to predict disease outbreaks. This will enable growers to time, and also reduce, their applications of fungicide. A greenhouse experiment is planned for this fall to determine the forward and backward action of four fungicides against phomopsis infection. The results of this experiment will provide some recommendations for growers on what fungicides to apply when using the model. In support of sustainable agriculture, a field trial is underway to evaluate the effectiveness of four biocontrol agents and two organic (sulfur and copper) treatments on their effect to inactivating overwintering inoculum in grapevines. Additionally, a project to evaluate the effectiveness of removal of leaf litter in reducing powdery mildew and downy mildew infections is under way. 4. Evaluate the efficacy of integrated disease management methods Fungicide efficacy trials were conducted for disease control in grapes, blueberries, raspberries and strawberries to evaluate new fungicide products as well as biological control agents and reduced-risk fungicides. Most products and fungicide programs showed good disease control efficacy. Trials from a USDA-NIFA grant are underway to determine the efficacy of biofumigation with mustard seed meal, and fresh plant material: mustard (two varieties), sudangrass (two varieties), and oilseed radish (two varieties). Anaerobic soil disinfestation (ASD) trials are also underway using rice bran, sugar beet pulp, dried alfalfa, corn silage, hay and cull-potato ferment against plant parasitic nematodes. Seven varieties of virus-free blueberry plants (Bluecrop, Duke, Liberty, Bluegold, Huron, Draper, and Aurora) have been planted into a field with high levels of tobacco ringspot virus (TRSV) and the Xiphimema nematode, a plant-parasitic nematode and the TRSV vector. The blueberry plants will be tested over the next 3 years for the presence of TRSV to assess each variety's level of resistance to nematodes and TRSV. Two similar fields are planned to test a variety of allegedly resistant rootstocks used in grapes and peaches for resistance to nematodes and TRSV infection.

Publications

• Type: Journal Articles Status: Published Year Published: 2016 Citation: McArt, S.H., Miles, T. D., Rodriguez-Saona, C., Schilder A., Adler, L.S., Brieshop M.J. 2016. Floral Scent Mimicry and Vector-Pathogen Associations in a Pseudoflower-Inducing Plant Pathogen System. Plos One. 11: e0165761.doi:10.137 1/journal.pone.0165761.
• Type: Journal Articles Status: Published Year Published: 2016 Citation: Arango, J., Rubino, M., Auras, R., Gillett, J., Schilder, A., Grzesiak, A.L. 2016. Evaluation of chlorine dioxide as an antimicrobial against Botrytis cinerea in California strawberries . Food Packaging and Shelf Line 9: 45-54.
• Type: Journal Articles Status: Published Year Published: 2016 Citation: Fitzgerald, K., Gillett, J., Schilder, A. 2016. Fungicide sensitivity of Monilinia vaccinii-corymbosi in highbush blueberries in Michigan. Phytopathology 106: S72.
• Type: Journal Articles Status: Published Year Published: 2016 Citation: Kotamraju, G., Sysak, R., Gillett, J., Schilder S. 2016.Utility of compost tea for disease management in grapes. Phytopathology 106: S79
• Type: Journal Articles Status: Published Year Published: 2016 Citation: Yamagata, J., Warneke, B., Neill, T., Mahaffee, W.,Miles, L., Schilder, A. 2016. Detection of Erysiphe necator fungicide-resistant alleles in leaf and air samples using novel molecular diagnostic techniques. Phytopathology 106: S111.
• Type: Journal Articles Status: Published Year Published: 2016 Citation: Dabbah, G., Schilder, A. 2016. Field observations of ascospore discharge of Monilinia vaccinii-corymbosi in northern highbush blueberries. Phytopathology 106: S132.

Progress 03/01/16 to 09/30/16

Outputs
Target Audience:The primary target audience for the project is small fruit growers, nursery owners, extension personnel and private consultants in Michigan and the Great Lakes region. in addition, the project reaches small fruit growers and other stakeholders throughout the United states and the world. Furthermore, undergraduate and graduate students are being educated in small fruit disease diagnosis and management as part of this project. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?The project provided training opportunities for one graduate student (Master's degree)and two undergraduate students in research and statistical analysis techniques. Atechnician improved her skills in quantitativePCR methods via a specialized training course. The PI improved her skills in statistical analysis by participating inshort statistical analysis courses. How have the results been disseminated to communities of interest?Results have been disseminated to communities of interest via oral and posterpresentations at extension and scientific meetings, refereed journal articles andbooks/bookchapters, extension newsletters, and pages on crop-specific university websites. Information has also been disseminated verbally directly to growers and consultants, in the form ordisease diagnoses and disease management commendations. What do you plan to do during the next reporting period to accomplish the goals?We plan to continue trials as set out in the project plan.

Impacts
What was accomplished under these goals? A better understanding of the identity and biology of small fruit pathogens is helping growers use the most appropriate fungicides and optimize fungicide timing for disease control. Growers are using more environmentally friendly fungicides and more growers are starting to grow fruit in a sustainable manner.Research on dormant sprays has led to adoption of dormant spraysby many small fruit growers in Michigan and the region.Studies on the environmental requirements for infection are forming the basis for disease-forecasting models that predict infection periods for small fruit diseases. This is anticipated to result in improved disease control and a concomitant reduction in fungicide applications. Efficacy testing of reduced-risk fungicides, biological control products, natural products, and inorganic substances has led to a diversification of disease control options and reduced the dependency ofgrowers on conventional fungicides.Information on fungicide resistance is helping growers choose more effective fungicides and implement fungicide resistance management techniques.Our research on virus diseases in grapes,blueberries and raspberries has increased awareness of virus problems in small fruit crops, resulting in changes in management practices, such as increased use of certified virus-tested plant material. Our research also feeds information into the Berry Clean Plant Network which has been established to produce virus-free foundation stock to nurseries. Results from this project are expected to have environmental, worker, and consumer benefits by reducing chemical use in fruit production. The project helps to maintain short-term and long-term viability of small fruit production in the United States. 1) Improve diagnosis of diseases and assessment of losses on small fruit crops We have run surveys for blueberry, grape and raspberry viruses and have discovered several new aphid-transmittedviruses in raspberry that have not been detected in Michigan before. In addition, Tomato ringspot virus and Raspberry bushy dwarf virus appear to be the most common causes of crumbly fruit and plant decline in Michigan.Leafroll viruses (particularly GLRaV-3) and the grapemealybugvector were found to becommon in vineyards in Michigan, particularly in the southwestern part of the state. A loss assessment was done for Phomopsis twig blight simulated by removal of different percentages of flowers at bloom in blueberries. There appeared to be a considerable amount of compensation for flower lossin Bluecrop and Jersey and a little less so in Liberty blueberries. Novel berry crops like saskatoonberries (juneberries) and haskaps (honeyberries) are being evaluated for diseases as it is not known what diseases would attack them when grown in a new area. Phytophthora root rot was diagnosed in Saskatoonberries due to heavy mulching. Due to the hot dry summer, most other problems were insect related. A problem with Saskatoonberries dying in another sites was determined to be due to trunkfreeze injury. We continue to observe the plants for diseases through the fall. 2) Elucidate the biology and population characteristics of small fruit pathogens We evaluated genetic diversity in Monilinia vaccinii-corymbosi from blueberryat the species level and found that Michigan isolates were very similar to each other. However, there were no good ITS sequences available in Genbank to confirm the species identification, which is still in progress in collaboration with Cornell University who have type specimens of the fungus. We also looked at species-level diversity in Colletotrichum from blueberry - so far all isolates are in the C. acutatum sensu lato complexand matched C. fioriniae. Genetic diversity was assessed in Grapevine virus E isolates from Michiganby Dr. Naidu RayapatiofWashington State University. GVE isolates from one vineyard were unique to Michigan and different from any other known isolates of GVE. 3) Effects of environmental factors and fungicides on small fruit pathogens. We evaluated the effects of environmental variables on ascospore release by M. vaccinii-corymbosi. Temperature and RH had significant effects on spore release with higher temperatures and lower RH being correlated with higher aerial ascospore concentration. Apothecial cup diameter was also positively correlated withaerial ascospore concentration.Fungicide sensitivity in M. vaccinii-corymbosito severaltriazoles (fenbuconazole, metconazole and prothioconazole)(FRAC group 3) and penthiopyrad (FRAC group 7) wasdetermined. There was noevidence for fungicide resistance in M.vaccinii-corymbosi, although a slight shift to reduced sensivity was detected in fields with a history of morefungicide applications.Colletotrichum fioriniae isolates from blueberry were also evaluated and some showedreducedsensitivity to strobilurin (QoI) fungicides, which have been widely used in blueberries for the past 15 years. This reconfirms the need for continued vigilance regardingfungicide resistance management.Pre- and post-infection activity of selected fungicides against Phomopsis vaccinii were evaluated and results are currently being analyzed. The Phomopsis twig blight incubation period is 5-7 days.Research was conducted in tunnel-grown raspberries to determine the effect of different plastics (UV- blocking, UV-transparent) on fungal spore survival of Colletotrichum fioriniae and Botrytis cinerea as well as persistence of fungicides used for small fruit disease control (captan, elevate, pyraclostrobin, boscalid, myclobutanil, cyprodinil and fludioxonil). Preliminary results indicateincreased spore survival and higher fungicide residue retentionunderUV-blocking plastic. 4) Evaluate the efficacy of integrated disease management methods Fungicideefficacy trials were conducted for disease control in grapes, blueberries and strawberries to evaluate new fungicide productsas well as biological control agents, compost teasand reduced-riskfungicides. Compost teas were also tested in organic apples and greenhouse tomatoes.Most products and fungicide programsshowed good disease control efficacy. Compost teas showed efficacy against powdery mildew and black rot but not much against downy mildew, due to high disease pressure in late summer. We are in the process of identifying the active ingredientsthat provide disease suppression in compost teas as well as studyingsurvival of compost tea bacteria on leaf surfaces. We also determined the effect of different types ofcompost tea drenches on oat and bean growth, soil pH and nutrients and soil enzymes. In a past trial, compost teamade from Dairy Doo compost increased K and P content of the soilsignificantly as well as slightly increasing the pH. Trials areunderway to determine the efficacy of biofumigation with mustard seed meal and anaerobic soil disinfestation (ASD) with rice bran against dagger nematodes in raspberries and black root rot in strawberries. In anintegrated pest management project in grapes, diseases were rated throughout the season, and IPM pesticide programs compared to conventional programs. Both programs performed equally well for disease control. Disease pressure was light during most of the season but increased in late summer due to heavy rains and high relative humidityin August and early September. Downy mildew infection led to significant defoliation of vines in some vineyards.

Publications

• Type: Book Chapters Status: Published Year Published: 2016 Citation: Schilder, A. M. C., Ramsdell, D. C., and Polashock, J. 2016. Shoestring. Chapter in: Compendium of Blueberry, Cranberry, and Lingonberry Diseases and Insects, 2nd ed. J. Polashock, F. Caruso, A. Averill, and A. Schilder, editors. American Phytopathological Society Press, St. Paul, MN.
• Type: Book Chapters Status: Published Year Published: 2016 Citation: Schilder, A. M. C., and Cline, W. O. 2016. Cylindrocladium rot. Chapter in: Compendium of Blueberry, Cranberry, and Lingonberry Diseases and Insects, 2nd ed. J. Polashock, F. Caruso, A. Averill, and A. Schilder, editors. American Phytopathological Society Press, St. Paul, MN.
• Type: Book Chapters Status: Published Year Published: 2016 Citation: Ramsdell, D. C., and Schilder, A. M. C. 2016. Peach rosette mosaic. Chapter in: Compendium of Blueberry, Cranberry, and Lingonberry Diseases and Insects, 2nd ed. J. Polashock, F. Caruso, A. Averill, and A. Schilder, editors. American Phytopathological Society Press, St. Paul, MN.
• Type: Book Chapters Status: Published Year Published: 2016 Citation: Schilder, A. M. C., Milholland, R. D., and Stretch, A. W. 2016. Powdery mildew. Chapter in: Compendium of Blueberry, Cranberry, and Lingonberry Diseases and Insects, 2nd ed. J. Polashock, F. Caruso, A. Averill, and A. Schilder, editors. American Phytopathological Society Press, St. Paul, MN.
• Type: Book Chapters Status: Published Year Published: 2016 Citation: Milholland, R. D. and Schilder, A. M. C. 2016. Botryosphaeria stem canker. Chapter in: Compendium of Blueberry, Cranberry, and Lingonberry Diseases and Insects, 2nd ed. J. Polashock, F. Caruso, A. Averill, and A. Schilder, editors. American Phytopathological Society Press, St. Paul, MN.
• Type: Book Chapters Status: Published Year Published: 2016 Citation: Schilder, A. M. C., and Ramsdell, D. C. 2016. Leaf mottle. Chapter in: Compendium of Blueberry, Cranberry, and Lingonberry Diseases and Insects, 2nd ed. J. Polashock, F. Caruso, A. Averill, and A. Schilder, editors. American Phytopathological Society Press, St. Paul, MN.
• Type: Book Chapters Status: Published Year Published: 2016 Citation: Schilder, A. M. C., and Ramsdell, D. C. 2016. Phomopsis canker. Chapter in: Compendium of Blueberry, Cranberry, and Lingonberry Diseases and Insects, 2nd ed. J. Polashock, F. Caruso, A. Averill, and A. Schilder, editors. American Phytopathological Society Press, St. Paul, MN.
• Type: Book Chapters Status: Published Year Published: 2016 Citation: Schilder, A. M. C., and Bristow, P. R. 2016. Red leaf. Chapter in: Compendium of Blueberry, Cranberry, and Lingonberry Diseases and Insects, 2nd ed. J. Polashock, F. Caruso, A. Averill, and A. Schilder, editors. American Phytopathological Society Press, St. Paul, MN.
• Type: Journal Articles Status: Published Year Published: 2016 Citation: Schilder, A. M. C., Gillett, J. M., and Sysak, R. W. 2016. Evaluation of fungicide programs for control of sour rot and powdery mildew in grapes, 2015. Plant Disease Management Reports 10:SMF041.
• Type: Journal Articles Status: Published Year Published: 2016 Citation: Schilder, A. M. C., Gillett, J. M., and Sysak, R. W. 2016. Evaluation of fungicides for control of fruit rot diseases in matted-row strawberry, 2015. Plant Disease Management Reports 10:SMF042.
• Type: Journal Articles Status: Published Year Published: 2016 Citation: Schilder, A. M. C., Gillett, J. M., and Sysak, R. W. 2016. Evaluation of fungicides for control of Botrytis gray mold in red raspberries, 2015. Plant Disease Management Reports 10:SMF043.
• Type: Journal Articles Status: Published Year Published: 2016 Citation: Schilder, A. M. C., Gillett, J. M., and Sysak, R. W. 2016. Evaluation of phosphites alone and in programs for control of foliar and fruit diseases in juice grapes, 2015. Plant Disease Management Reports 10:SMF044.
• Type: Journal Articles Status: Published Year Published: 2016 Citation: Schilder, A. M. C., Gillett, J. M., and Sysak, R. W. 2016. Evaluating fungicides for control of mummy berry and post-harvest anthracnose fruit rot in blueberries, 2015. Plant Disease Management Reports 10:SMF009.
• Type: Journal Articles Status: Published Year Published: 2016 Citation: Schilder, A. M. C., Gillett, J. M., and Sysak, R. W. 2016. Evaluation of fungicides for control of Botrytis bunch rot and powdery mildew, 2015. Plant Disease Management Reports 10:SMF011.
• Type: Journal Articles Status: Published Year Published: 2016 Citation: Schilder, A. M. C., Gillett, J. M., and Sysak, R. W. 2016. Evaluating fungicides for control of post-harvest fruit rots in blueberries, 2015. Plant Disease Management Reports 10:SMF012.
• Type: Journal Articles Status: Published Year Published: 2016 Citation: Schilder, A. M. C., Gillett, J. M., and Sysak, R. W. 2016. Evaluation of systemic fungicide programs for control of powdery mildew, 2015. Plant Disease Management Reports 10:SMF013.
• Type: Conference Papers and Presentations Status: Other Year Published: 2016 Citation: Schilder, A., R., Gillett, J., Sysak, R., and Miles, T. 2016. Sustainable approaches to blueberry disease management in Michigan. 11th International Vaccinium Symposium, Orlando, FL, 10-14 Apr, 2016 (poster).
• Type: Conference Papers and Presentations Status: Other Year Published: 2016 Citation: Percival, D., Guo, L., Harris, L., Schilder, A., Prithiviraj, B., and Olson, A. R. 2016. Integration of laboratory fungicide sensitivity analysis into Monilinia blight management technologies for wild blueberry production. 11th International Vaccinium Symposium, Orlando, FL, 10-14 Apr, 2016 (poster).
• Type: Other Status: Published Year Published: 2016 Citation: Martinson, T., Fuchs, M., Puckett, J., Kelly, M., Schilder, A., Burr, T. and Nita, M. 2016. Clean plants for the future of the Eastern wine and grape industry. Research Focus article in Appellation Cornell http://grapesandwine.cals.cornell.edu/newsletters/appellation-cornell.
• Type: Book Chapters Status: Published Year Published: 2016 Citation: Schilder, A. M. C., Gillett, J. M., and Sysak, R. W. 2016. Evaluation of fungicides for control of disease in Vignoles grapes, 2015. Plant Disease Management Reports 10:SMF014.
• Type: Other Status: Published Year Published: 2016 Citation: Elsner, E., Schilder, A., and Isaacs, R. 2016. Saskatoonberry Pesticide Recommendations for Michigan. Michigan State University Extension, 10 pp (pdf).
• Type: Conference Papers and Presentations Status: Other Year Published: 2016 Citation: Rodriguez-Saona, C., McArt, S. H., Miles, T. D., Schilder, A., Adler, L. S., Grieshop, M. J. 2016. Floral scent mimicry and vector-pathogen associations in a pseudoflower-inducing plant pathogen system. International Society of Chemical Ecology, Iguazu, Brazil, 2016.
• Type: Conference Papers and Presentations Status: Other Year Published: 2016 Citation: Fitzgerald, K., Gillett, J., and Schilder, A. 2016. Fungicide sensitivity of Monilinia vaccinii-corymbosi in highbush blueberries in Michigan. American Phytopathological Society Meeting, 30 Jul-3 Aug, 2016, Tampa, FL.
• Type: Conference Papers and Presentations Status: Other Year Published: 2016 Citation: Kotamraju, G., Sysak, R., Gillett, J. and Schilder, A. 2016. Utility of compost tea for disease management in grapes. American Phytopathological Society Meeting, 30 Jul-3 Aug, 2016, Tampa, FL.
• Type: Conference Papers and Presentations Status: Other Year Published: 2016 Citation: Dabbah, G., Miles, T., and Schilder, A. 2016. Field observations of ascospore discharge of Monilinia vaccinii-corymbosi in northern highbush blueberries. American Phytopathological Society Meeting, 30 Jul-3 Aug, 2016, Tampa, FL.
• Type: Conference Papers and Presentations Status: Other Year Published: 2016 Citation: Schilder, A., Martin, R., Gillett, J., and Miles, T. 2016. Diagnosis and management of new and re-emerging diseases of highbush blueberries in Michigan. 11th International Vaccinium Symposium, Orlando, FL, 10-14 Apr, 2016.
• Type: Other Status: Published Year Published: 2016 Citation: Schilder, A. 2016 Warm weather favors anthracnose fruit rot in strawberries. MSU Extension News for Agriculture (http://news.msue.msu.edu/news/category/ fruit). Posted on Jun 24, 2016.
• Type: Other Status: Published Year Published: 2016 Citation: Schilder, A. Young grape clusters are susceptible to attack from fungal diseases. MSU Extension News for Agriculture (http://news.msue.msu.edu/news/category/ fruit). Posted on June 21, 2016.
• Type: Other Status: Published Year Published: 2016 Citation: Schilder, A. Disease activity picking up in grapes. MSU Extension News for Agriculture (http://news.msue.msu.edu/news/category/ fruit). Posted on June 15, 2016.
• Type: Other Status: Published Year Published: 2016 Citation: Schilder, A. Mysterious yellow spots on grape leaves are not downy mildew. MSU Extension News for Agriculture (http://news.msue.msu.edu/news/category/ fruit). Posted on June 10, 2016.
• Type: Other Status: Published Year Published: 2016 Citation: Schilder, A. Update on Luna fungicides for grapes and berry crops. MSU Extension News for Agriculture (http://news.msue.msu.edu/news/category/ fruit). Posted on May 10, 2016.
• Type: Other Status: Published Year Published: 2016 Citation: Baughman, B., Mason, K., and Schilder, A., and Isaacs, R. 2016. Vineyard IPM scouting report for May 17, 2016. MSU Extension News for Agriculture (http://news.msue.msu.edu/news/category/ fruit). Posted on May 17, 2016.
• Type: Other Status: Published Year Published: 2016 Citation: Baughman, B., Mason, K., Schilder, A., and Isaacs, R. 2016. Vineyard IPM scouting report for June 30, 2016. MSU Extension News for Agriculture (http://news.msue.msu.edu/news/category/ fruit). Posted on Jun 30, 2016.
• Type: Other Status: Published Year Published: 2016 Citation: Baughman, B., Mason, K., and Isaacs, R. and Schilder, A. 2016. Vineyard IPM scouting report for July 26, 2016. MSU Extension News for Agriculture (http://news.msue.msu.edu/news/category/ fruit). Posted on Jul 26, 2016.
• Type: Other Status: Published Year Published: 2016 Citation: Mason, K., Schilder, A., and Isaacs, R. 2016. Vineyard IPM scouting report for Aug 25, 2016. MSU Extension News for Agriculture (http://news.msue.msu.edu/news/category/ fruit). Posted on Aug 25, 2016.
• Type: Other Status: Published Year Published: 2016 Citation: Baughman, B., Mason, K., and Schilder, A. 2016. Vineyard IPM scouting report for Sep 6, 2016. MSU Extension News for Agriculture (http://news.msue.msu.edu/news/category/ fruit). Posted on Sep 6, 2016.
• Type: Journal Articles Status: Awaiting Publication Year Published: 2016 Citation: McArt, S. H., Miles, T. D., Rodriguez-Saona, C., Schilder, A. M. C., Adler, L. S., and Grieshop, M. 2016. Floral scent mimicry and the transmission of a pollinator-vectored plant pathogen. PLoS ONE (in press)
• Type: Books Status: Published Year Published: 2016 Citation: Polashock, F. Caruso, A. Averill, and A. Schilder (eds.). 2016. Compendium of Blueberry, Cranberry, and Lingonberry Diseases and Insects, 2nd ed. J. American Phytopathological Society Press, St. Paul, MN.
• Type: Book Chapters Status: Published Year Published: 2016 Citation: Schilder, A. M. C. 2016. Algal stem blotch. Chapter in: Compendium of Blueberry, Cranberry, and Lingonberry Diseases and Insects, 2nd ed. J. Polashock, F. Caruso, A. Averill, and A. Schilder, editors, American Phytopathological Society Press, St. Paul, MN.
• Type: Book Chapters Status: Published Year Published: 2016 Citation: Schilder, A. M. C., Bristow, P. R., and Milholland, R. D. 2015. Botrytis blight and fruit rot. Chapter in: Compendium of Blueberry, Cranberry, and Lingonberry Diseases and Insects, 2nd ed. J. Polashock, F. Caruso, A. Averill, and A. Schilder, editors. American Phytopathological Society Press, St. Paul, MN.
• Type: Book Chapters Status: Published Year Published: 2016 Citation: Schilder, A. M. C., and Ramsdell, D. C. 2016. Necrotic ringspot. Chapter in: Compendium of Blueberry, Cranberry, and Lingonberry Diseases and Insects, 2nd ed. J. Polashock, F. Caruso, A. Averill, and A. Schilder, editors. American Phytopathological Society Press, St. Paul, MN.
• Type: Book Chapters Status: Published Year Published: 2016 Citation: Schilder, A. M. C., and Milholland, R. D. 2016. Phomopsis twig blight and fruit rot. Chapter in: Compendium of Blueberry, Cranberry, and Lingonberry Diseases and Insects, 2nd ed. J. Polashock, F. Caruso, A. Averill, and A. Schilder, editors. American Phytopathological Society Press, St. Paul, MN.