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Bugs - Bug Review - University of Illinois Extension

Squash Bug

Adult squash bugs are brownish-black insects about 5/8 inch long. Both adults and nymphs have a disagreeable odor if crushed. Newly hatched nymphs have a reddish head and legs and green bodies which change and darken as they age.

Habit

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Squash bug adult

Adult squash bugs appear in spring and feed and lay eggs on squash or related crops. Eggs are light to dark brown, about 1/16 inch long and usually deposited in neat clusters on the underside of leaves or on stems. In one to two weeks, young nymphs emerge and remain in clusters for some time. They become adults in about five weeks. There is one generation per year.

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Squash bug adults and nymphs

Damage

The squash bug damages crops by sucking plant sap from leaves of squash, pumpkin, and related crops. Attacked leaves wilt rapidly and become black and crisp, as if the flow of sap has been cut off. In the early season, young vine crops are easily killed; older plants may have runners damaged or killed. Winter varieties of squash, such as the Hubbard, are most severely injured.

Control

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Squash bugs feeding on zucchini

Chemical: Adult squash bugs are very difficult to kill. Examine crops regularly so that insecticide applications can be applied when young bugs are present.