Diseases of Cucurbits
Angular Leaf Spot
Pseudomonas syringae pv. lachrymans
• All; most serious on cucumbers • Seed-borne• Infested crop residue• Splashing water, insects & mechanically • Clean seed• Resistant cultivars• Crop rotation (2 years)• Copper fungicides
Downy MildewPseudoperonospora
cubensis
• All cucurbits
• Windborne, rain-splash & mechanically• Favored by
warm days with cool nights leading to dew periods of rainfall with prolonged leaf wetness
•Resistant varieties (cucumber) •Fungicides
Powdery Mildew Spaerotheca fuliginea & Erisyphe cichoracearum
• All cucurbits
• Windborne • Favored by warm, dry days with cooler nights
• Resistant varieties• Fungicides
AnthracnoseColletotrichum orbiculare
Primarily cucumbers, melons and watermelons
Survives on infected crop residues Can be seedborne Wind & rain splash Resistant varieties Clean seed Destroy crop residue Fungicides Crop rotation (1 year)
Gummy Stem Blight
Didymella bryoniae (Phoma
cucurbitacearum) All cucurbits
Survives on infected crop residues Can be seed-borne Wind & rain splash Destroy crop residue Treated seed Fungicides Crop rotation (2 year)
Fusarium WiltFusarium oxysporum f.
sp. niveum
• Watermelon
• Soilborne • Avoid fields with a history of the disease• Crop rotation (3-5 years)• Resistant varieties
David Langston University of Georgia
Bacterial Wilt
Erwinia tracheiphila
• All but watermelon; most serious on cucumbers and pumpkins
• Survives in asymptomatic weed hosts (?) • Insecticides• Rogue infected plants
Papaya Ringspot Virus type W (PRSV-W)
Watermelon Mosaic Virus (WMV)
Zucchini Yellow Mosaic Virus (ZYMV)
Cucurbit Viruses (potyviruses)
• All cucurbits
• Survive in a variety of weed hosts
• Aphid-transmitted in non-persistent manner
• Resistant varieties• Mineral oils• Reflective mulches
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