Carolina Farm Stewardship Association    2012 Sustainable Agriculture Conference  Sustainable and Organic  Approaches To M...
Today’s Outline    Intro to Tomato and Cucurbit Diseases        Important Pathogens        Risks to Other Crops    5 G...
Avoid extremes“You can’t grow organic vegetables in the  Southeast.”“All diseases can be managed organically.”
Symptoms of Important TomatoDiseases--Root Disease          Leaves Stem Crown Roots   Fruit Bacterial wilt    **    **    ...
Spread and Survival of ImportantTomato Pathogens--Root                                Spread                              ...
Host Range of Important TomatoDiseases--Root                                               Other     Other     Br-LfDiseas...
Symptoms of Important TomatoDiseases--FoliarDisease                Leaves Stem Crown   Roots   FruitBacterial speck/spot  ...
Spread and Survival of ImportantTomato Pathogens--Foliar                                                        Survive in...
Host Range of Important TomatoDiseases--Foliar                                                Other   Other     Br-LfDisea...
The Disease TriangleAn Aid to Management               Host               Plant               Disease Environment         ...
The Disease Triangle forGummy Stem Blight Watermelon                Didymella                Environment
Host Range of Important CucurbitDiseases                                            Winter                                ...
Symptoms of Important CucurbitDiseases Disease              Leaves   Crown   Vine   Fruit Downy mildew           √ Powdery...
Spread and Survival of ImportantCucurbit Pathogens                                        Spread                          ...
Diseases that Affect BothCucurbit and Tomato Crops   Phytophthora               Southern blight    crown and fruit rot  ...
5 General Control   Strategies      Avoidance     Protection    Resistance    Eradication    Exclusion
Challenges with Spraying for OrganicDisease Control (Protection) Favorable environment Biopesticides usually less effect...
What is AVOIDANCE?    Preventing contact     between pathogen     and host to prevent     disease.    Modifying the     ...
Avoidance Techniques         Change planting date         Raise beds to prevent              damping-off       Avoid wetti...
Eradication: Length of CropRotationsFoliar pathogens               Soilborne pathogens   No long-term survival         V...
2 Crop Rotation and PlantingSchemes for Small Acreages   For foliar diseases:         For root and wilt      Spread cro...
Foliar                          Soilborne                            pathogens                       pathogensSeparate or ...
Soil Solarization                     Sterilizing soil by using                    heat from the sun trapped              ...
Composting to EliminatePathogens   Eradication of                      Nematodes   Fungi   Seeds    pathogens in plant   ...
General Cultural Practices to AvoidDisease on All Crops          Reduce leaf wetness          •Drip irrigation          •I...
Controlling Vegetable Diseases-General Organic Techniques    Bacteria                       Fungi (true)        Reduce ...
General Cultural Practices toManage Tomato Diseases          Grafting          •Root knot          •Southern blight       ...
Resistant Tomato VarietiesResistance Available     No Resistance Spotted wilt              Bacterial spot Early blight ...
Gray Leaf Spot ‘Cherokee Purple’ is v. susceptible 2-3 year rotation Avoid planting tomato and pepper next to  each oth...
Phytophthora crown and fruit rot
Phytophthora capsiciSporangia—                    Oospore—•   Form on infected plants   • Forms in/on fruit•   Spread by/i...
Controlling Phytophthoracrown and fruit rot—Water management       Raised beds       • Cut water furrows       • Don’t pun...
Controlling Phytophthoracrown and fruit rot—Soil management        Mulch--Plastic or organic        Wash equipment        ...
Cucurbit Downy Mildew
Controlling Cucurbit DownyMildew          Copper sprays          • On crops other than            cucumber          Avoida...
Cucurbit Powdery Mildew
Controlling Cucurbit PowderyMildew         Biopesticides—spray top and bottom         of leaves         • Organocide (fish...
Gummy Stem Blight
Anthracnose
Survival of the GSB Fungus in                                   Cantaloupe Crowns                                     Nov ...
Controlling Gummy Stem Blightand Anthracnose         Rotate for 3 years         • Summer squash in 2nd or 3rd year        ...
Managing Fusarium Wilt ofWatermelon   Resistant cultivars       Only resist. to race 1   Grafting onto    bottlegourd o...
Managing Bacterial FruitBlotch See conventional  guidelines Only exception is  avoid use of  Actigard
Managing Cucurbit VirusesSpread by Aphids   Resistant cultivars       Check if conventional        or GM   Horticultura...
Sustainable DiseaseManagement  Organic soil           Cultural  management             practices                 Check pla...
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Cfsa cucurbits and tomatoes 2012

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Cfsa cucurbits and tomatoes 2012

  1. 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. 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. 3. Avoid extremes“You can’t grow organic vegetables in the Southeast.”“All diseases can be managed organically.”
  4. 4. Symptoms of Important TomatoDiseases--Root Disease Leaves Stem Crown Roots Fruit Bacterial wilt ** ** * * -- Southern -- -- ** * (*) blight Fusarium wilt ** * -- (*) -- Root knot -- -- -- ** --
  5. 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. 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. 7. Symptoms of Important TomatoDiseases--FoliarDisease Leaves Stem Crown Roots FruitBacterial speck/spot ** (*) -- -- *Gray leaf spot ** -- -- -- --Early blight ** * -- -- *Late blight ** * -- -- **Spotted wilt ** * -- -- **
  8. 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. 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. 10. The Disease TriangleAn Aid to Management Host Plant Disease Environment Pathogen
  11. 11. The Disease Triangle forGummy Stem Blight Watermelon Didymella Environment
  12. 12. Host Range of Important CucurbitDiseases Winter Summer Squash/ Cuke Melon Watermelon Squash Pumpkin GourdsDowny ** ** * * ** *mildewPhytophthora * -- ** ** ** *Powdery ? * ** ** * *mildewGummy * ** ** -- * *stem blightAnthracnose ** (*) * -- * **
  13. 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. 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. 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. 16. 5 General Control Strategies Avoidance Protection Resistance Eradication Exclusion
  17. 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. 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. 19. Avoidance Techniques Change planting date Raise beds to prevent damping-off Avoid wetting leaves when watering Mulch to prevent fruit rots
  20. 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. 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. 22. Foliar Soilborne pathogens pathogensSeparate or Group Related Tomato Solanaceous Squash Arugula Cucurbits EggplantCrops? & Broccoli Cukes Pepper Brassicas
  23. 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. 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. 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. 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. 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. 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. 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. 30. Phytophthora crown and fruit rot
  31. 31. Phytophthora capsiciSporangia— Oospore—• Form on infected plants • Forms in/on fruit• Spread by/in water • Survives in soil
  32. 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. 33. Controlling Phytophthoracrown and fruit rot—Soil management Mulch--Plastic or organic Wash equipment • Between fields • Newly purchased or borrowed Remove cull fruit
  34. 34. Cucurbit Downy Mildew
  35. 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. 36. Cucurbit Powdery Mildew
  37. 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. 38. Gummy Stem Blight
  39. 39. Anthracnose
  40. 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. 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. 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. 43. Managing Bacterial FruitBlotch See conventional guidelines Only exception is avoid use of Actigard
  44. 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. 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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