Egg - Roughly diamond- or spindle-shaped, each egg is white when first deposited but gradually turns yellowish-brown and finally dark bronze. It is approximately 1.5 mm long and 1 mm wide. Arranged in a checker-like pattern, eggs typically occur on the foliage in masses of 20 to 40.
Nymph - The five nymphal instars range in length from 2.5 to 10 mm. The first instar is green with rose-colored legs, antennae, and head. These appendages darken in a few hours. Subsequent instars are grayish-white with dark heads, legs, and antennae. The last two instars have noticeable wing pads.
Host Plants - All cucurbit vine crops are subject to squash bug infection. The bugs prefer squash, pumpkin, cucumber, and melon, in that order. Hubbard, winter, and marrow squash are often heavily infested.
Damage - Feeding in colonies, adults and nymphs pierce vines with their needle-like mouthparts. While feeding, they inject a toxic substance into plants. As a result, vines quickly turn black and dry out. This aspect of squash bug damage superficially resembles bacterial wilt symptoms. Small plants and individual runners of large vines are often destroyed. When infestations are heavy, fruit may not form. If fruit does develop, bugs may congregate and feed on unripe fruit itself.
Life History - Squash bugs overwinter as unmated adults under plant debris or other suitable shelter. When cucurbit vines start to run in spring, squash bugs fly into gardens and mate. Over a period of several weeks, eggs are laid on undersides of leaves, typically in the angles formed by leaf veins. One or 2 weeks later, depending on the temperature, nymphs hatch from the eggs and begin to feed. Four to 6 weeks pass before nymphs develop into adults. Because of the prolonged egg-laying period, nymphs and adults are present throughout summer. Feeding continues until frost forces adults into hibernation. One generation occurs each year.
In small gardens, adult squash bugs and leaves with egg masses can be handpicked and destroyed. The bugs can also be trapped by placing small boards near the host vines. Squash bugs gather under the boards at night and are easily collected and destroyed the next morning.
Should a significant infestation develop, insecticide recommendations and rates can be found in the current North Carolina Agricultural Chemicals Manual.
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