Getting Powdery Mildew Under Control in Cucurbits, and Updates on Fungicides
for Vegetables
Mohammad BabadoostUniversity of [email protected]
Powdery Mildew of Cucurbits and Its
Management
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Cucurbits___________________________________ Melons Cucumbers Gourds Pumpkins (JOL & processing) Squash (summer & winter) Watermelon
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Cantaloupe Cucumber
Squash WatermelonPowdery mildew on cucurbits
Powdery Mildew: pumpkinBabadoost
Powdery Mildew: Pathogens_____________________________________ Two fungal species Podosphaera xanthii Erysiphe cichoracearum
Identification: difficult (sexual stage is not common)
We began identifying species
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Reproductive bodies of Podosphaera xanthii
Reproductive bodies of Erysiphe cichoracearum
Powdery Mildew: Symptoms_____________________________________ Symptoms & Sings Powdery fungal growth
(Mycelium and conidia) Infected tissues Vines Petioles Upper and lower leaf surfaces Fruit stems
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Powdery Mildew: vine infection
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Powdery Mildew: lower surface of leaf
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Powdery Mildew: upper surfaces of leaves
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Powdery Mildew: fruit stem
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Powdery Mildew: fruit stemsBabadoost
Powdery mildew fungus on plantsBabadoost
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Disease Cycle of Powdery Mildew
Cucurbits
Fungal Characteristics ____________________________________ Obligate parasite (biotrophic) Heterothalic (mating types) Sexual state: cleistothecium Asexual state: conidia Feed on epidermal cells Races have been documented
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Powdery Mildew Characteristics Occurrence: annually occurring Initial inoculum: conidia Inoculum sources: southern states and
greenhouses Conidia viability: 7-8 days Disease cycle: in 3-7 Favored: dryness with RH (50-100%) Temperatures: 50-90°F (68-80°F) Rain and water: unfavorable Yield losses: significant Babadoost
Susceptibility of Cucurbits to Powdery Mildew in the Midwest More susceptible cucurbits Squash (summer & winter) Pumpkins (JOL) Melons
Less susceptible cucurbits Cucumbers Processing pumpkinsWatermelons Babadoost
Expected Time for Powdery Mildew in Illinois and Indiana______________________________________ South: around July 15 Central and North: after July 20
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Important Management Point ______________________________________ Powdery mildew develops first
on vines Then, powdery mildew moves
onto lower leaf surfaces Powdery mildew on upper leaf
surfaces indicates outbreaks
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Powdery mildew on pumpkin Babadoost
Powdery mildew on cucurbits is the same
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Management of cucurbit Powdery Mildew _________________________________
Cultural management Plant resistance Biocontrol Chemical control
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Powdery Mildew Management ______________________________________
Cultural management Crop rotation Avoid shade areas Scout the field for powdery
mildew on vines and lower leaf surfaces
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Powdery Mildew Management ______________________________________
Plant resistance Resistant cultivars: many
resistant/tolerant cultivars of cantaloupe, cucumber, squash, pumpkin
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Crop Cultivar Crop CultivarCucumber Cyclone Pumpkin Big Moon
Thunder Jack-Be-LittleSlice King Magic Lantern
Melon Laguna MerlinAll Start MysticApolloOro DuroRocio
Squash HurakanSungloPatriot
Cucurbits Resistant/Tolerant to Powdery Mildew
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Management of cucurbit Powdery Mildew ______________________________________
Biocontrol AQ10 (Ampelomyces quisqualis),
fungus (Ecogen) Mycotal (Lecanicillium lecanii),
fungus (Koppert Biological Sys.) Serenade (Bacillus subtilis),
bacterium (AgraQuest) Babadoost
Powdery Mildew Management ______________________________________
Chemical control ˃ 15 Fungicides available
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Pumpkin & Squash:Cabrio (11)Flint (11)Fontelis (7)Inspire Super (3,9)Microthiol (S) (M)Merivon (7,11) Pristine (7,11)Procure (3)Quadris (11)Quadris Opti (11,M)Quintec (13)Rally (3)Topsin M (1)Torino (U6)
Cantaloupe, Cucumber, Watermelon:
Flint (11), Fontelis (7)Inspire Super (3,9)Luna Experience (3,7)Luna Sensation (7,11)Merivon (7,11)Microthiol (S) (M)Pristine (7,11)Procure (3), Quadris (11)Quadris Opti (11,M)Quintec (13)Rally (3), Satori (11)Topsin M (1), Torino (U6)
Fungicides for Cucurbit Powdery Mildew
Fungicides for Cucurbit Powdery MildewFRAC Fungicides Fungicide Group - Risk
1 Topsin M MBC (Methyl Benzimidazole Carbamates)
(Cell division) - High risk
3 Inspire Super, Procure, Rally, Luna Experience
DMI (Dethylation Inhibitors)(Cell membrane) - Medium risk
7 Fontelis, Merivon, Pristine, Luna Experience, Luna Sensation
SDHI (Succinate dehydrogenase inhibitors) (Respiration)- Medium-highrisk
9 Inspire Super AP (Anilino-pyrimidines) (Protein synthesis) - Medium risk
11 Cabrio, Flint, Merivon, Pristine, Quadris, Quadris Opti, Luna Sensation, Satori
Strobilurin: QoI (Quinone outside Inhibitors) (Respiration)- High risk
13 Quintec (Aza-naphthalenes) (Signal transduction) - Medium risk
M2 Microthiol (S) (Inorganic) (Multi-site activity) Low risk
U6 Torino (Phenyl-acetamide), Unknown
Fungicides for Cucurbit Powdery Mildew_______________________________________Most effective fungicides in my trials:
Quintec, Procure, Fontelis, Torino, Pristine, Quadris Opti, MicrothiolQuintec was the most effective Alternate Quintec with another fungicideStrobilurins are good for 10-14 days,
others for 7 days (max: 10 days)3-6 sprays are neededScout inside canopy, apply at first signPlan for spray during Jul 20 – Sep 10
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Updates on Vegetable Diseases______________________________________ 2015 Vegetable Production Guide Table 33 (pages 74-76): common and
scientific names of vegetable pests Table 12 (page 37): yields of vegetables
(updates)White rust: added to cole crops Bacterial fruit blotch: new recommendat. Merivon fungicide: cole crops, Brassica
leafy green, cucurbits, onion chapter Priaxor fungicide (7+11): fruiting vegetables Aoroach fungicide (11): legumes
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Updates on Vegetable Diseases______________________________________Cucurbit Disease Bacterial spot: a serious disease on
pumpkins, gourds, and winter squash. No effective control yet.
Sclerotinia blight of pumpkins: problem Edema: problem in white pumpkins Downey mildew: seed-borne reported Downy mildew control: chlorothalonil
prior to infection; Revus, Ranman, Zampro, Gavel … + chlorothalonil with disease sign infection
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Bacterial spot on squash fruit
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Collapse of pumpkin fruit infected by Xanthomonas cucurbitae
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Updates on Vegetable Diseases_____________________________________Cucurbit Disease Bacterial spot: a serious disease on
pumpkins, gourds, and winter squash. No effective control yet. Quintec fungicide has some effects
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BabadoostPumpkins with Sclerotinia sclerotiorum
BabadoostPumpkins with Sclerotinia sclerotiorum
Updates on Vegetable Diseases_____________________________________Cucurbit Disease Sclerotinia blight of pumpkins:
serious problem some years. Fontelis can be considered.
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Edema on white pumpkin in IL in 2014
Updates on Vegetable Diseases_____________________________________Cucurbit Disease Edema: problem in white pumpkins
(Moonshine)
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Downy mildew on cucumberBabadoost
Updates on Vegetable Diseases_____________________________________Cucurbit Disease Downey mildew: seed-borne reported Downy mildew control: chlorothalonil
prior to infection; Revus, Ranman, Zampro, Gavel … + chlorothalonil with disease sign infection
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Updates on Vegetable DiseasesOther Vegetable Disease Basil downy mildew: a serious disease,
effective control with either Quadris, Revus, or Ranman + ProPhyt
Tomato leaf mold (Vulvia fulva): now in indoor and outdoor production
Tomato white mold: now in more prevalent in high tunnel production
Tomato bacterial diseases: spot, speck, and canker. Bacterial spot is prevalent. Sprays of Quintec + Kocide-3000 alternated with mancozeb + Kocide-3000 suppress the disease.
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Downy mildew of basil on leaves
Updates on Vegetable DiseasesOther Vegetable Disease Basil downy mildew: a serious disease,
effective control with either Quadris, Revus, or Ranman + ProPhyt
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Leaf mold of tomato in a high tunnel Babadoost
Updates on Vegetable DiseasesOther Vegetable Disease Tomato leaf mold (Vulvia fulva):
now in indoor and outdoor production
Fungicides:ChlorothalonilMancozebInspire SuperQuadris TopTanos
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White Molds (Sclerotinia sclerotiorum)Babadoost
White Molds (Sclerotinia sclerotiorum)Babadoost
Updates on Vegetable DiseasesOther Vegetable Disease Tomato white mold: now in more
prevalent in high tunnel production.
Fungicides: Cabrio (11)Cantans (biological fungicide,Coniothyrium minitans strain CON/M/91-08) Priaxor (11)
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Bacterial SpeckBacterial SpotBacterial Canker
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Bacterial spot
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Updates on Vegetable DiseasesOther Vegetable Disease Tomato bacterial diseases: spot, speck,
and canker. Bacterial spot is prevalent. Sprays of Quintec + Kocide-3000 alternated with mancozeb + Kocide-3000 suppress the disease.
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Questions/Comments