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.
Squash bugs overwinter as unmated adults under plant debris or other suitable shelter. They emerge in late April or early May, search for suitable hosts, and mate. Eggs are laid over a period of several weeks, on undersides of leaves, typically in the angles formed by leaf veins. One or 2 weeks later, nymphs hatch from the eggs and begin to feed. Four to 6 weeks pass before nymphs develop into adults. Due to the extended egg-laying period, nymphs and adults are present throughout summer. Feeding continues until frost kills nymphs and forces adults into hibernation. There are 3-4 generations each year.
Eggs are roughly diamond or spindle-shaped, each egg is white when first deposited but gradually turns yellowish-brown and finally dark bronze. 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. The adult bug is dark brown, mottled with light gray on its back side and mottled yellow on its underside. About 16 mm long, it is flat across it's back and gives off a disagreeable odor when crushed.
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, which superficially resembles bacterial wilt symptoms. Small plants and individual runners of large vines are often destroyed. Heavy infestations may affect fruit production and bugs may congregate and feed on unripe fruit itself. Squash bugs can increase in numbers quite rapidly and can cause plants to wilt just by sheer numbers.
For control, utilize proper fertilization and plant resistance varieties. In small gardens, adult bugs and leaves with eggs masses can be hand-picked and destroyed.