by National Gardening Association Editors
Adult squash bugs are 5/8" long.
Squash bugs are found throughout the United States. Adult bugs are flat-backed, brown, and about 1/2 inch long; the immature nymphs resemble adults but are pale colored with black legs. This insect attacks all kinds of cucurbits, but it usually prefers squashes and pumpkins. Adults and nymphs feed by sucking juices from leaves, causing leaves to wilt, dry up, and turn black.
Adults overwinter under plant debris or in the soil. They usually emerge about the time vines begin to "run." Females lay clusters of reddish-brown or bronze-colored eggs on the undersides of leaves. There is a single generation per year.
Prevention and Control
Choose squash varieties resistant to the pest. Lay shingles or boards in the garden at night; bugs will hide under them during the day, and you can collect and destroy hiding bugs first thing in the morning. Crush any egg clusters you find on the undersides of leaves.
Photography by Whitney Cranshaw, Colorado State University, Bugwood.org