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