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

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

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.

Azamax Botanical Insecticide, Miticide, & Nematicide [Organic]
Active ingredient: azadirachtin | EPA reg no: 71908-1-81268
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.

Images

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Caption: Squash bug adult and nymphs Photo by: Unknown

WSU Extension

Hortsense