How to Manage Pests

Pests in Gardens and Landscapes

Squash bug—Anasa tristis

Adult squash bugs are 0.63 inch long, grayish or yellowish brown, flatbacked, and somewhat speckled, often with a dense covering of black hairs. Edges of the abdomen are orange or orange and brown striped. Nymphs are pale green to almost white.

Life cycle

Eggs are laid in the spring through midsummer on stems or on the undersides of leaves, often in the angle formed where two veins meet. The orange yellow to bronze eggs are elliptical, and are deposited on their sides in groups. Young squash bugs are wingless and pale green to almost white, later turning darker brown. Very young nymphs feed close together. Nymphs grow into adults by late summer or fall. There are several generations a year.


Leaves develop small specks that turn yellow and later brown; plants may wilt and die.


Remove all debris from the garden once the crop is harvested by composting or thoroughly discing or rototilling it under. Handpick adult bugs and nymphs; search for and destroy eggs in the spring and early summer. Trap bugs under boards near plants at night and destroy them in the morning. Garden insecticides are not very effective, especially on larger bugs. Insecticidal soap or neem oil may control the smallest nymphs.

For more information, see the Squash Bug Pest Note.

Adults are found mating in the field
Adults are found mating in the field

Squash bug nymphs
Squash bug nymphs

Feeding causes wilting of some plants
Feeding causes wilting of some plants

Statewide IPM Program, Agriculture and Natural Resources, University of California
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