Phytophthora in Peppers and Cucurbits

Mohammad Babadoost University of Illinois Email: [email protected] Phytophthora Blight (Phytophthora capsici) ______Importance:  Worldwide occurrence  Affects >50 species in 15 plant families  The most important disease of peppers and cucurbits in the US  Causes up to 100% crop losses

Babadoost Phytophthora blight of bell pepper Babadoost Phytophthora crown infection of peppers Babadoost Phytophthora blight of, 100% crop losses

Babadoost Phytophthora blight of pepper Babadoost Plant death of pumpkin (Phytophthora capsici) Babadoost Phytophthora crown infection of a squash plant Babadoost Phytophthora foliar blight and fruit rot of squash Babadoost Fruit rot of cucurbits (Phytophthora capsiciBabadoost) Fruit rot of pumpkins (Phytophthora capsici) Babadoost Phytophthora Blight (Phytophthora capsici) ______ An oomycete pathogen  Genetic and pathogenic variat ions  Mult i-cycle pathogen  Survival: oospores and m ycelium

 Favorable condit ions: m oist & Babadoost w arm Phytophthora capsici

Babadoost Management of Phytophthora Blight of Peppers and Cucurbits ______ Resistant cultivars  Chemical control  Cultural practices

Babadoost Management of Phytophthora Blight of Peppers and Cucurbits ______

 Resistant cultivars  Chemical control  Cultural practices

Babadoost Cucurbit seedling death caused by Phytophthora capsici Babadoost Evaluating pepper cultivars for resistance to Phytophthora capsici

Babadoost Evaluating pepper cultivars for resistance to Phytophthora capsiciBabadoost Management of Phytophthora Blight of Peppers and Cucurbits ______

 Resistant cultivars  No resistant cucurbit cultivar  Resistant pepper cultivars are available

Babadoost Pepper Cultivars Resistant/Tolerant to Phytophthora Blight ______Results of greenhouse and field trials  Alliance  Aristotle  Emerald Isle  Enza  Paladin  Reinger  Revolution Babadoost Management of Phytophthora Blight of Peppers and Cucurbits ______ Resistant cultivars

 Chemical control  Cultural practices

Babadoost Phytophthora Blight of Peppers and Cucurbits (Chemical Control) ______ Since 2000, we have tested more than 40 fungicides for their efficacy for control of Phytophthora capsici

Babadoost Phytophthora Blight Management (Chemical Control) ______ 2000-2009: Spray application  2010: Drip-irrigation delivery

Babadoost Babadoost Fungicides for Control of Phytophthora capsici ______ Effective Fungicides ** Cyazofamid (Ranman 400SC) ** Captan (Maestro 80DF) * Dimethomorph (Forum 4.16SC ) ** Famoxadon + Cymoxanil (Tanos 50WDG) * Fluopicolide (Presidio 4SC) ** Mandipropamid (Revus 2.09SC) * Mefenoxam (Ridomil G. EC 4SC, R. G. Copper 65WP) • Phosphorous acid (ProPhyt) – inconsistent results • (Zampro 525SC) – further studies needed No fungicide is effective with heavy rainfalls Fungicides Control of Phytophthora capsici (Organic Production) ______No effective fungicide is available for control of P. capsici in organic production

Babadoost Management of Phytophthora Blight of Peppers and Cucurbits ______ Resistant cultivars  Chemical control

 Cultural practices

Babadoost Management of Phytophthora Blight of Peppers and Cucurbits ______ Cultural practices  Crop rotation  Host range of the pathogen  Survival of the pathogen in soil

Babadoost Phytophthora Blight Management (Host Range: 36 Crops and 9 Weed Species) ______

Host______Non-Host______. Cantaloupe Cucumber Gourd Corn Pigweed Soybean Eggplant pepper Beet Broccoli Kale Cabbage Pumpkin Squash Radish Crabgrass Basil Chive Zucchini Watermelon Turnip Sandbur Celery Dill Honeydew Swiss-chard Carrot Wheat Water hemp Barley Spinach Nightshade Onion Cocklebur Lamb’s-quarters Green bean Lima bean Tomato Mustard Cauliflower Velvet-leaf Snow pea Tobacco Parsley Puncture vine Babadoost 100 100 5,000 Oospores/g soil 90 Depth: 80 2 cm 70 60.6 10 cm 60 25 cm 50 Average 40 30 20 16.7 10.1 % Oospores% recovered 10 0.9 0.4 0.06 0.04 0.004 0

Oospore survival in soil Babadoost 70 5,000 Oospores/g soil Depth: 60 53.2 2 cm 50 47.2 10 cm 25 cm 40 Average 30 30.0 20.8 20 15.5

7.6

% Oospores% germinated 10 2.7 2.5 0.0 0

Germination of oospores recovered Management of Phytophthora Blight of Peppers and Cucurbits ______

 Cultural practices There are NONHOST crops of Phytophthora capsici  Phytophthora capsici may survive in soil for 4 years

Babadoost Managing Phytophthora Blight in Organic Pepper Production ______ Grow resistant cultivars  ≥3 years effective crop rotations  Grow in field with no Phytophthora history  Grow on raised beds  Use straw mulch between rows  Sanitation practices  Avoid using contaminated water

 Tolerant cultivars with cultural practicesBabadoost Managing Phytophthora Blight in Organic Cucurbit Production ______ No resistant cucurbit is available  Grow in field with no Phytophthora history  ≥3 years effective crop rotations  Grow on well-drained field  Grow on raised beds, if possible  Disk localized infected areas  Sanitation practices  Avoid using contaminated water Babadoost Disk localized area with Phytophthora infection

Babadoost QUESTIONS