Back in March I found one of these squash bugs (Anasa tristis, Coreidae) overwintering in a rotting tree here in southern Michigan. Now that it’s warm and their favorite food plants are flourishing, they’re out in force. I found a number of them crawling around on some zucchini plants (Cucurbita pepo, Cucurbitaceae) in a local greenhouse.
The adjacent greenhouse had some yellow summer squash plants in it (a different variety of Cucurbita pepo). They were infested with a closely related insect, the horned squash bug (Anasa armigera, Coreidae).
Both of these bugs are considered common and serious pests of vegetable plants in the family Cucurbitaceae (squash, melons, pumpkins, and cucumbers). They feed on plant sap which causes the leaves to wilt, turn brown, and die. They can also vector diseases in these plants. Anasa tristis, the bug shown here, is probably the more common threat.