WSU Extension


Cucumber, Pumpkin, Squash
Angular leaf spot 
Cucumber mosaic virus 
Curly top (Beet curly top virus) 
Pollination failure 
Powdery mildew 
Root rot 
Verticillium wilt 
White mold 
Brown marmorated stink bug 
Spider mites 
Squash bug 
Western spotted cucumber beetle 

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Caption: Squash bug adult and nymphs
Photo by: Unknown
Cucumber, Pumpkin, Squash : Squash bug
(revision date: 2/14/2019)

The squash bug attacks squash, pumpkin, melons, and related crops. Adults are typically dark brown, but may have gray or light brown markings. They are about 3/4" long at maturity. Brown to reddish eggs are laid along the veins of new leaves. The newly hatched nymphs (immature bugs) are greenish to gray. Squash bug nymphs and adults feed on the leaves, causing small yellow specks which later turn brown. Squash bugs also inject a toxin into vines which causes a wilt from the point of attack to the end of the vine. Affected runners wilt and turn black and crisp. Small plants may be killed, while larger plants may lose several runners. Squash bugs may also attack young fruit. Adult squash bugs overwinter in debris and sheltered places in the garden.
Management Options

Non-Chemical Management
  • Hand-pick and destroy eggs, nymphs, and adults.
  • Clean up debris in the fall to remove overwintering squash bugs.
Select non-chemical management options as your first choice!

Chemical Management

Esfenvalerate products are toxic to bees. Do not apply any of the products listed on or near blooming plants. To minimize risk to bees, apply in the evening after bees have stopped foraging for the day.

Listed below are examples of pesticides that are legal in Washington. Always read and follow all label directions.
  • Bug Buster-O [Organic]
    Active ingredient: pyrethrins  |  EPA reg no: 1021-1771-54705
  • Safer Brand BioNEEM Multi-Purpose Insecticide & Repellent Conc [Organic]
    Active ingredient: azadirachtin  |  EPA reg no: 70051-6-42697
  • This list may not include all products registered for this use.

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Caption: Squash bug adult and nymphs
Photo by: Unknown