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Cfsa cucurbits and tomatoes 2012

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  • 1. Carolina Farm Stewardship Association 2012 Sustainable Agriculture Conference Sustainable and Organic Approaches To ManagingCucurbit and Tomato Diseases Anthony (Tony) Keinath Vegetable Pathologist Clemson University Coastal REC Charleston, SC
  • 2. Today’s Outline  Intro to Tomato and Cucurbit Diseases  Important Pathogens  Risks to Other Crops  5 General Control Strategies  Avoidance  Eradication  Recommendations for Specific Diseases  “More of what works, less of what doesn’t”
  • 3. Avoid extremes“You can’t grow organic vegetables in the Southeast.”“All diseases can be managed organically.”
  • 4. Symptoms of Important TomatoDiseases--Root Disease Leaves Stem Crown Roots Fruit Bacterial wilt ** ** * * -- Southern -- -- ** * (*) blight Fusarium wilt ** * -- (*) -- Root knot -- -- -- ** --
  • 5. Spread and Survival of ImportantTomato Pathogens--Root Spread Rain Survive in Disease Organism Wind Splash Water Soil Bacterial Bacterium -- -- ** ** wilt Southern Fungus -- -- -- ** blight Fusarium Fungus -- -- -- ** wilt Root knot Nematode -- -- -- **
  • 6. Host Range of Important TomatoDiseases--Root Other Other Br-LfDisease Pepper Eggplant Potato Cucurbits Veg. Crops WeedsBacterial ** ** * -- -- tobacco *wilt geraniumFusarium -- -- -- -- -- -- --wiltSouthern ** ** (*) (*) beans, (*)blight sun peanut chokeRoot knot ** ** ** ** *** ** *
  • 7. Symptoms of Important TomatoDiseases--FoliarDisease Leaves Stem Crown Roots FruitBacterial speck/spot ** (*) -- -- *Gray leaf spot ** -- -- -- --Early blight ** * -- -- *Late blight ** * -- -- **Spotted wilt ** * -- -- **
  • 8. Spread and Survival of ImportantTomato Pathogens--Foliar Survive inDisease Organism Wind Rain Splash Water SoilBacterial Bacterium * ** -- *speck/spotGray leaf Fungus ** **spotEarly blight Fungus * * -- *Late blight Water ** * -- (*) moldSpotted wilt Virus -- -- -- --
  • 9. Host Range of Important TomatoDiseases--Foliar Other Other Br-LfDisease Pepper Eggplant Potato Cucurbits Veg. Crops WeedsBacterial ** -- -- -- -- -- --speck/spot (spot)Gray leaf ** (*) -- -- -- -- *spotEarly blight -- (*) ** -- -- -- (*)Late blight -- -- ** -- -- petunia *Spotted wilt ** -- * -- -- peanut ** tobacco
  • 10. The Disease TriangleAn Aid to Management Host Plant Disease Environment Pathogen
  • 11. The Disease Triangle forGummy Stem Blight Watermelon Didymella Environment
  • 12. Host Range of Important CucurbitDiseases Winter Summer Squash/ Cuke Melon Watermelon Squash Pumpkin GourdsDowny ** ** * * ** *mildewPhytophthora * -- ** ** ** *Powdery ? * ** ** * *mildewGummy * ** ** -- * *stem blightAnthracnose ** (*) * -- * **
  • 13. Symptoms of Important CucurbitDiseases Disease Leaves Crown Vine Fruit Downy mildew √ Powdery mildew √ Phytophthora crown √ √ √ √ and fruit rot Gummy stem blight √ √ (√) √ and black rot Anthracnose √ √ √
  • 14. Spread and Survival of ImportantCucurbit Pathogens Spread Rain Survive Disease Organism Wind Splash Water in Soil Downy mildew Water Mold ** (*) -- -- Powdery mildew Fungus ** -- -- -- Phytophthora Water Mold crown and fruit -- * ** ** rot Gummy stem blight and black Fungus * ** -- * rot Anthracnose Fungus (*) ** -- *
  • 15. Diseases that Affect BothCucurbit and Tomato Crops Phytophthora  Southern blight crown and fruit rot  Tomato, pepper,  Pepper, tomato, eggplant eggplant  Snap bean  Snap and lima  Jerusalem artichoke beans  Peanut Root knot  Many broad-leaved crops
  • 16. 5 General Control Strategies Avoidance Protection Resistance Eradication Exclusion
  • 17. Challenges with Spraying for OrganicDisease Control (Protection) Favorable environment Biopesticides usually less effective than conventional fungicides  Powdery mildew is exception NOP allows S and Cu only as a last resort  Protectants only Labels of biopesticides are inaccurate
  • 18. What is AVOIDANCE?  Preventing contact between pathogen and host to prevent disease.  Modifying the environment to make it less favorable for disease.  One of 2 main strategies for organic disease control.  Warning: pathogen is still present!
  • 19. Avoidance Techniques Change planting date Raise beds to prevent damping-off Avoid wetting leaves when watering Mulch to prevent fruit rots
  • 20. Eradication: Length of CropRotationsFoliar pathogens Soilborne pathogens No long-term survival  Various survival structures structures Until infested debris is  Sclerotia gone  Oospores  ≤ 1 yr for bacteria  Dormant mycelia  1-3 yr for fungi and  Cannot eradicate with water molds rotation  Can reduce populations (= primary inoculum)
  • 21. 2 Crop Rotation and PlantingSchemes for Small Acreages For foliar diseases:  For root and wilt  Spread crops in diseases: same botanical  Group crops in family far apart same botanical  Slows pathogen family together spread  Rotate away for 3-4 Disadvantage: Makes years crop rotation difficult  Disadvantage: May increase foliar diseases in wet years
  • 22. Foliar Soilborne pathogens pathogensSeparate or Group Related Tomato Solanaceous Squash Arugula Cucurbits EggplantCrops? & Broccoli Cukes Pepper Brassicas
  • 23. Soil Solarization Sterilizing soil by using heat from the sun trapped under clear plastic by the “greenhouse effect” Solarize Solarizing soil potting is PARTIALLY soil in effective clear plastic bags 2 wk 8 Use 2 weeks layers in plastic June- July
  • 24. Composting to EliminatePathogens Eradication of Nematodes Fungi Seeds pathogens in plant 180 debris 160 D To be safe: e 140  Peak temperatures g 120 147-158 F. for 21 r 100 days e 80 e  Difficult to achieve s 60 in 1-cu-ft pile 40 Survived: F 20  Fusarium wilt of tomato 0
  • 25. General Cultural Practices to AvoidDisease on All Crops Reduce leaf wetness •Drip irrigation •Increase row/plant spacing •Avoid edges of woods •Row orientation Improve soil drainage • Raised beds • Add organic matter • Compost • Cover crops
  • 26. Controlling Vegetable Diseases-General Organic Techniques  Bacteria  Fungi (true)  Reduce leaf wetness  Copper does not work  One- to two-year  Sulfur is better option rotation  Water molds  Copper (oomycetes)  Root diseases and  Copper nematodes  Potassium phosphite  Improve soil drainage  Not organic certified  Increase organic matter  Resistance
  • 27. General Cultural Practices toManage Tomato Diseases Grafting •Root knot •Southern blight •Fusarium wilt •Bacterial wilt •(awaytogarden.com) High Tunnels • Prevent fruit cracking • Reduce foliar disease • Extend season • (hightunnel.org, Kansas State)
  • 28. Resistant Tomato VarietiesResistance Available No Resistance Spotted wilt  Bacterial spot Early blight  Bacterial wilt Root knot  Southern blight Late blight  ‘Mountain Magic’ (campari type)  Resistance in All  ‘Plum Regal’ Hybrids  Gray leaf spot  Fusarium wilt  Except grapes
  • 29. Gray Leaf Spot ‘Cherokee Purple’ is v. susceptible 2-3 year rotation Avoid planting tomato and pepper next to each other Early planting  Disease is favored by high temp and humidity
  • 30. Phytophthora crown and fruit rot
  • 31. Phytophthora capsiciSporangia— Oospore—• Form on infected plants • Forms in/on fruit• Spread by/in water • Survives in soil
  • 32. Controlling Phytophthoracrown and fruit rot—Water management Raised beds • Cut water furrows • Don’t punch holes too deeply Do not use surface water Drip irrigation Avoid planting low areas
  • 33. Controlling Phytophthoracrown and fruit rot—Soil management Mulch--Plastic or organic Wash equipment • Between fields • Newly purchased or borrowed Remove cull fruit
  • 34. Cucurbit Downy Mildew
  • 35. Controlling Cucurbit DownyMildew Copper sprays • On crops other than cucumber Avoidance • Early planting date Resistance • C. maxima • Cucumber cultivars • Tolerant • ‘Aladdin’ pumpkin • Some summer squash cv.
  • 36. Cucurbit Powdery Mildew
  • 37. Controlling Cucurbit PowderyMildew Biopesticides—spray top and bottom of leaves • Organocide (fish oil + sesame oil) • Potassium bicarbonate • JMS Stylet Oil or horticultural oil Sulfur • Do not apply at 90ºF Resistant summer and winter squash and pumpkin cultivars from Harris Seeds
  • 38. Gummy Stem Blight
  • 39. Anthracnose
  • 40. Survival of the GSB Fungus in Cantaloupe Crowns Nov 05 May 06 Nov 06 May 07 Nov 07 100 % Crowns with viable D. bryoniae Soil surface% Crowns with viable D. bryoniae 90 Plastic mulch 100 Soil surface 80 Buried 5 in. 90 Plastic mulch 80 70 70 60 60 50 50 40 40 30 30 20 20 10 10 0 0 0 10 20 30 40 50 60 70 80 90 100 0 10 20 30 40 50 60 70 Weeks after burial Weeks after burial
  • 41. Controlling Gummy Stem Blightand Anthracnose Rotate for 3 years • Summer squash in 2nd or 3rd year Plant early Disease-free transplants Do not reuse plastic mulch Disk fields to bury debris as soon as possible after harvest
  • 42. Managing Fusarium Wilt ofWatermelon Resistant cultivars  Only resist. to race 1 Grafting onto bottlegourd or hybrid squash  Both are susceptible to root knot  Crop rotation to Hairy vetch as winter reduce build-up of cover crop/green pathogen manure  Works best before soil is infested
  • 43. Managing Bacterial FruitBlotch See conventional guidelines Only exception is avoid use of Actigard
  • 44. Managing Cucurbit VirusesSpread by Aphids Resistant cultivars  Check if conventional or GM Horticultural oil sprays  Every other day  Prevent infection Camouflage  Rye grass between rows Kaolin clay sprays
  • 45. Sustainable DiseaseManagement Organic soil Cultural management practices Check plants • Cover crops • Exclude, weekly for • Crop rotation • Eliminate and problems • Compost • Avoid disease Identify diseases to Apply select the best biopesticides control method preventatively •Bacterium or fungus? •Water mold or true fungus?

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