Cucumber, Pumpkin, Squash: Curly top (Beet curly top virus)

Biology

Curly top is caused by a virus transmitted by the beet leafhopper. Many crops are affected, including tomato, bean, squash, cucumber, and pepper. In cucumbers, growth is slow and older leaves are yellowed. The terminal leaves may be unusually dark, and the plant is stunted. Yield is low, and fruits are small and of poor quality. Young squash plants may be killed without showing symptoms. Older plants show yellowing of older leaves, dwarfed new growth, overall stunting, and upward rolling of leaves. Runners often bend upward at the tip. Diseased plants may fail to set fruit. The virus is also found in annual flowers and weeds. Curly top is not a problem in western Washington.

Management Options

Use Integrated Pest Management (IPM) for successful plant problem management.

Non-chemical Management

Select non-chemical management options as your first choice!

• Pull out and destroy infected plants.
• Control of beet leafhoppers is ineffective for preventing curly top.
• Since leafhoppers avoid feeding on shaded plants, shading plants may help prevent infection.
• There are no resistant cucumber varieties. The squash varieties ‘Umatilla Marblehead’ and ‘Yakima Marblehead’ show resistance.

Chemical Management

IMPORTANT: Visit Home and Garden Fact Sheets for more information on using pesticides.

• None recommended