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V3 organic control options

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Organic Control Options for Vegetable Diseases

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V3 organic control options

  1. 1. Common diseases of vegetable crops in New Brunswick, 2014-16 Michael Tesfaendrias, Ph.D., P. Ag. NBDAAF IPM Specialist (Plant Pathologist) (506) 453 3478 Michael.tesfaendrias@gnb.ca
  2. 2. Plant Disease • Infectious (biotic) – Fungi (early blight) – Bacteria (soft rot) – Nematode (stem and bulb nematode) – Protozoa (club root) – Phytoplasma (aster yellows) – Virus (iris yellow spot) • Non-infectious (abiotic) – Too low or too high Temp. – Drought or excessive moisture – Lack or excess light – Air pollution – Nutrient deficiency, mineral toxicity, soil pH – Pesticide toxicity – Improper cultural practices
  3. 3. • Infectious (biotic) • Noninfectious (abiotic)
  4. 4. Disease Development Disease can be prevented upon elimination/manipulation of any one of the disease triangle components Susceptible Host Pathogen Environment (favourable) Disease
  5. 5. Role of insects in plant diseases • Insects can transmit disease (virus, phytoplasma) • Wounds created by insect feeding: ideal entry point for pathogens Aster yellows Onion thrips Tarnished plant bug Fungal spores Aster leafhopper
  6. 6. Flea beetle Cabbage maggot
  7. 7. Vegetable disease management • Integrated Pest Management (IPM): an approach to managing pests that uses all available strategies to reduce pest populations below an economic injury level. – Monitoring: weather conditions, plant health, disease symptoms – Cultural methods: site selection, crop rotation, resistant/tolerant cultivar, disease free seed (planting material) sanitation, remove alternate host, optimize plant health – Biological control methods – Chemical control Holistic approach
  8. 8. Common diseases of tomato • Late blight (Phytophthora infestans) – Infects Solanaceae plants – High moisture, high RH and moderate temp. (10-21 ºC) – Sever defoliation and fruit rot – Introduced: on infected tomato transplants, infected seed potatoes, volunteer plants, cull piles • Produce millions of spores wind-borne and spread into nearby fields
  9. 9. Needs 7-10 days between spore deposition and lesion development (Infection) Spore produced in 7-10 hours of moist period Late blight
  10. 10. Late blight
  11. 11. Late blight management • Select resistant cultivars • Transplant healthy seedlings • Regularly monitor your fields • Remove and destroy infected plants • Measures to prevent further spread – Keep foliage as dry as possible, avoid watering plants in the late evening or early morning and do not over-fertilize. • Fungicide spray (short interval once the disease is detected)
  12. 12. Late blight resistant tomato cultivars?
  13. 13. Late blight resistant cultivar trial, 2016 • 5 sites • 11 cultivars • No late blight incidence
  14. 14. Early blight (Alternaria solani) – Infects leaves and fruits – Reduces plant vigor – Defoliated plants are subject to sunscald – Infection:17 - 24ºC and extended leaf wetness – Spore dispersal: water, wind, insects, other animals, and machinery
  15. 15. Courtesy APS Early blight
  16. 16. Early blight management • Remove and destroy crop residue or plow residue into the soil • Crop rotation (3-4 years) • Control volunteers and susceptible weeds • Good air circulation • Irrigate early in the day • Proper nutrient management • Minimize plant injury • Use resistant or tolerant varieties • Chemical/biological control
  17. 17. Powdery mildew (Oidium neolycopersici, Erysiphe lycopersici, Leveillula taurica)
  18. 18. Powdery mildew • Infection: warm, humid and fields under water stress • Most common in high tunnel than in field tomato Management • The best management is prevention • Select resistant varieties • Fungicide/biocontrol – Timing: no later than the first sign of disease – good coverage
  19. 19. Leaf mold (Fulvia fulva syn. Cladosporium fulvum) – Primarily a problem in greenhouses – Can affect field tomatoes – Most destructive (GH) during the fall, early winter, spring when relative humidity is high and heating is not continuous – High relative humidity: fungus develops rapidly • (RH ≥ 85%; 4º - 34ºC) – If not controlled, results leaf death yield loss
  20. 20. Leaf mold (Fulvia fulva syn. Cladosporium fulvum)
  21. 21. Leaf mold management • Keep the RH <85%, reduce leaf moisture period – Provide good air circulation – Warmer night temperatures – Avoid wetting the leaves – Maintain temperatures 16º to 18ºC – Adequate plant and row spacing (prevents excessive shading) • Select resistant cultivars (e.g. Deter Vs Indeterminate) • Reduce primary inoculum (e.g. sanitation) – Carefully remove and burn all plant debris
  22. 22. Cucurbits • Powdery mildew (Podosphaera xanthii) – Causes premature defoliation, affect yield and quality. Management • Sanitation • Selecting PM-tolerant cultivars (if available) • Fungicide spray
  23. 23. Downy mildew (Pseudoperonospora cubensis) Lesions on leaves are often restricted by leaf veins, giving the lesion an angular or square appearance Management -Use resistant varieties -Monitoring (crops and weather forecasts) -Site selection (air movement and without shading) -Irrigation (avoid early morning or late in the day). -Maintain nitrogen fertility
  24. 24. Alternaria leaf blight (Alternaria cucumerina) • Avoid working when plants are wet • Sanitation – remove fallen leaves from the greenhouse – Remove and destroy infected plants at the end of the season
  25. 25. Carrot Diseases • Cavity spot and pythium root dieback(Pythium spp.) • Sclerotinia rot (Sclerotinia sclerotiorum) • Crater rot; Crown rot (Rhizoctonia)
  26. 26. Carrot Diseases • Aster yellows • Leaf blight (Alternaria dauci and Cercospora carotae)
  27. 27. Allium Diseases Botrytis leaf blight Downy mildew (Peronospora destructor) • Stemphylium leaf blight (S. vesicarium) Botrytis neck rot • Purple blotch (A. porri)
  28. 28. Basal plate rot/nematode -Use clean seed (free of nematodes) -Crop rotation
  29. 29. Cole crops Alternaria leaf spot (Alternaria sp.) Management • Minimize leaf wetness period • Remove infected leaves and eliminate cull piles • incorporate plant debris into the soil • Crop rotation with non-host crops • Fungicide/biocontrol spray • Cool, wet and humid conditions favour • Older, senescing plant parts are more susceptible • Can spread by wind
  30. 30. Pathogens with wide host range • Botrytis cinerea • Sclerotinia sclerotiorum • Damping off and root rot (Pythium spp., Fusarium spp.)
  31. 31. Lettuce • Gray mould (Botrytis cinerea) – Wide range (>100: trees, vegetables, ornamentals, weeds) – Cool and humid conditions – Infects damaged tissues – Field lettuce: most serious in early spring and late fall
  32. 32. Botrytis gray mould (Botrytis cinerea)
  33. 33. Gray mould management • Cultural practices – Space plant adequately to provide good ventilation – Proper fertilization (e.g. N and Ca levels) – Sanitation: remove (eliminate) plant debris/cull piles – Proper irrigation/watering – GH: provide sufficient heat at night to prevent dew formation • Chemical/biological control
  34. 34. Fungal plant pathogen World wide distribution Omnivorous >400 plant host species Causes losses in the field and postharvest
  35. 35. Sclerotinia sclerotiorum White mould, sclerotinia rot, pink rot, cottony soft rot, drop, sclerotinia stem rot
  36. 36. Sclerotinia sclerotiorum • Soilborne or airborne pathogen • Survival structure: sclerotia • Germination of sclerotium  Myceliogenic (hyphal emergence) • Infection by mycelium at or beneath the soil-line  Carpogenic germination - produces apothecia with ascospores • Above ground infection  Both Myceliogenic and Carpogenic
  37. 37. S. sclerotiorum (white mould) management • Reduce viable sclerotia – rotation (≥ 3yr) with non-host crops – keep field free of weed – discard infected plants from the field – deep plowing to keep the sclerotia from soil surface • During and after harvest – do not mix infected with healthy crop (e.g. tomato) – store harvested produce into clean bins – proper storage temperature and ventilation • Biological control
  38. 38. Damping-off and Root rots • Pythium, Phytophthora, Rhizoctonia, Fusarium • Seedlings affected at ground level and topple over • Symptoms: seed decay, rotting roots and cankers on the stem or lower petioles • Damping-off: usually during the seedling stage – Cool and wet springs – Conditions that slow emergence and delay development • Root rots: can affect at any growth stage – Mostly warm, wet conditions
  39. 39. Damping-off management • Use sterile soil-less mixture to grow seedlings • Use clean (disease free seed) • Care not to crack or shatter seeds • Plant when soil and weather conditions are favourable for vigorous crop development • As soon as damping-off is detected, stop watering for a while – allow the soil to dry, but not completely dry • Chemical/bio-control (e.g. drench application)
  40. 40. Biological Control Options Organisms Product Name Targeted pests (examples) OMRI (√) Bacillus subtillus Serenade ASO Serenade Max Cease Early/late blight in tomato & potato Expanded label √ √ √ Bacillus subtillis Rapsody ASO Powdery/downy mildew √ Bacillus subtillis Subtilex Damping-off and root rot in greenhouse. Soil treatment - Coniothyrium minitans Contans WG Fungal diseases of some greenhouse veg. Soil treatments √ Gliocladium catenulatum Prestop Damping-off of greenhouse veg . and herbs. Soil and foliar treatments. √ Streptomyces Strain K61 Mycostop Damping off, root and stem rot. Soil and seed treatment - S. lydicus Actinovate Powdery mildew and gray mould √ Trichoderma harzianum Rootshield Rot diseases in greenhouse crops. Soil treatment √
  41. 41. Biopesticides Active Ingredients Product Name Targeted pest (examples) OMRI (√) Garlic Inflence LC & WP Buran Powdery mildew (PM) in greenhouse (Tomato & Cucumber) Powdery mildew cucumber - - Extract of Reynourtia Regalia Maxx Inducing plant defense mechanisms PM and bact. spot (pepper and tomato) Gray mould (tomato) √ Hydrogen Peroxide StorOx Fungicide/Bactericide: Fusarium tuber rot, Bacterial soft rot, silver scurf, Potato storage treatment √ Lactic/Citric acids Cyclone Tivano Lacto-san PM and DM greenhouse cucumbers PM on cucurbits, bact. canker (tomato) PM on cucurbits, bact. canker (tomato) - - - Saponins of chenopodium HeadsUp Fungicide/ Plant stimulant: Seed or pre- transplant seedling foliar treatment √
  42. 42. Biopesticides / Chemicals Active Ingredients Product Name Targeted pest (examples) OMRI (√) Copper hydroxide Parasol WG Kocide 2000 DF Coppercide Early/late blight in tomato & potato (Prevention only) √ (?) - - Copper oxychloride Copper Spray Fungicide - Hydrogen Peroxide StorOx Fusarium tuber rot, Bacterial soft rot, silver scurf, post harvest treatment √ Calcium polysulphide Lime sulphur Insecticide/ miticide/fungicide - Sulphur Kummulus DF Bartlett Micro. S UAP Micro. S PM greenhouse, peppers, peas √ - - Potassium bicarbonate MilStop Sirocco PM on tomato, pepper, cucurbits √ -
  43. 43. www.gnb.ca/content/gnb/en/departments/10/agricultureResources
  44. 44. Resources
  45. 45. PMRA http://hc-sc.gc.ca/cps-spc/pest Resources http://perennia.ca/
  46. 46. English and French names of diseases used in the presentation Insect Pests Cabbage maggot Flea beetle Mouche du chou Altise Tomato Late blight Early blight Powdery mildew Leaf mold Mildiou de la tomate Brûlure alternarienne Maladie du blanc Moisissure olive Cucurbits Powdery mildew Downy mildew Alternaria leaf blight Maladie du blanc Mildiou Alternariose Carrots Cavity spot Sclerotinia rot Crater and crown rot Aster yellows Leaf blight Maladie de la tache Moisissure blanche Rhizoctone et rhizoctone commune Jaunisse de l’ester Brûlure des feuilles Onions Botrytis leaf blight Stemphylium leaf blight Botrytis neck rot Purple blotch Downy mildew Basal rot/nematode Brûlure de la feuille Brûlure stemphylienne Pourriture du col Tache pourpre Mildiou Fusariose /Nématode Cole crops Alternaria leaf spot Alternariose Pathogens with wide host range Botrytis (Gray mould) Sclerotinia sclerotiorum Damping-off and root rot Botrytis (Moisissure grise) Sclerotinia sclerotiorum Fonte des semis et pourriture des racines
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Organic Control Options for Vegetable Diseases

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