Review of 2013 Vine Crop Diseases Chris Smart Plant Pathology and Plant- Microbe Biology Cornell University Geneva, NY
Growing vine crops has become difficult!
Common Diseases Powdery mildew Virus diseases Downy mildew Phytophthora blight
Powdery Mildew Podosphaera xanthii VERY common we see it every year Some varieties have resistance Kills leaves Sun scald Weakens handles in pumpkins More susceptible to some other diseases
Powdery Mildew Evidence that the pathogen can overcome some plant resistance This is still the way to go! That the pathogen can overcome some fungicides Effective fungicides (conventional and organic) are available
Common Diseases Powdery mildew Virus diseases Downy mildew Phytophthora blight
Virus Diseases Photo: Marc Fuchs Watermelon Mosaic present every year, arrives later in the season Cucumber Mosaic not here every year or in every field, arrives early Aphid transmitted Post bloom only foliar symptoms Pre-bloom fruit symptoms
Virus symptoms Cucumber Mosaic Photo: Marc Fuchs Watermelon Mosaic
Common Diseases Powdery mildew Virus diseases Downy mildew Phytophthora blight
Cucurbit Downy Mildew Pseudoperonospora cubensis Attacks all cucurbits cucumbers most susceptible
First symptom is a yellowing spot on the upper surface of the leaf Spots expand turning tan and papery, but are bordered by veins Lower leaf surface has gray spores Symptoms
Lesions
Bottom of Leaf
Mildews Powdery Mildew Downy Mildew
Downy Control The pathogen blows in either from the south, or from greenhouse production around lakes Erie and Ontario, and generally does not arrive until late July or August In Eastern NY, inoculum could come from either source, and usually arrives later in the season No commercially available resistant cucurbits but I am working with several breeders and we have high hopes! Vegetable news letters provide information on where downy has been reported Excellent website http://cdm.ipmpipe.org/ Sign up for alerts
Downy Control The downy mildew pathogen is closely related to Phytophthora (both are water molds), many fungicides that are effective against downy are also labeled for Phytophthora blight Many water-mold specific fungicides Broad-spectrum protectant fungicides provide some control Follow outbreaks and know when the pathogen is in the area
Common Diseases Powdery mildew Virus diseases Downy mildew Phytophthora blight
Phytophthora Blight Phytophthora capsici
Wide Host Range
Wilting and plant death Crown and root rot Fruit rot Stem and leaf lesions Symptoms
Phytophthora Blight Over winters as thickwalled spores in the soil Small white spores produced during the growing season, can t survive over winter Swimming spores also produced
What do spores look like? Sporangia Zoospores Oospores
How Does Phytophthora Move? Culled fruit Cultivation Soil (tractor tires) Rain water/splashing Irrigation water Flood water Does not move in air/wind
Surface Irrigation Water 60% of NY vegetables are irrigated with surface irrigation water
Irrigation Sources Creeks Irrigation Ponds Erie Canal
Surface Irrigation Water 60% of NY vegetables are irrigated with surface irrigation water Surveyed 20 sites across NY for Phytophthora capsici once a month for 2 years pathogen can be present in water Improving detection methods to identify pathogens quickly Comparing methods for decontamination
What are we working on now? Making great use of the blight farm
Blight Farm Five faculty now have P. capsici projects Testing different varieties for resistance Testing integrated control strategies Ways to improve soil health cover crops Pathogen detection Four 2-acre blocks, one block is organic
Management Strategies If you don t have Phytophthora blight KEEP IT OFF YOUR FARM! If you have Phytophthora blight Promote good drainage Choose tolerant varieties Rotate Rogue if possible Use effective fungicides (ROTATE CHEMISTRIES)
Management Strategies Commonly used fungicides Ranman Presidio (18-month plant-back restriction) Gavel Forum Revus Tanos Phosphorous acid fungicides Ridomil (perhaps once/season in Western NY)
Thanks! Smart lab members Grower cooperators Vegetable Extension Educators NYS Ag Expt Station NYS Dept of Ag and Mkts USDA - NIFA
Questions?