University of Illinois Extension
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Squash Bug
Squash and pumpkins


Squash bug is a common pest in pumpkins and squash in Illinois. Both the adults and nymphs feed on plants by sucking the juice. Yellow specks develop on the attacked leaves. The attacked leaves turn brown and die. They also attack the fruit and their feeding can lead to the collapse of the fruit or render it unmarketable. The adults overwinter under crop debris or in sheltered wooded areas close to the field/garden. The adults are dark-grayish brown in color and less than 1-inch long. They lay eggs in clusters on the underside of the leaves as from mid June. The eggs hatch in about one week into nymphs, which are pale green in color and become brown as they grow. In Illinois, it takes about a month for five nymphal stages to occur before the insect mature into an adult. The females mate and start laying eggs, which hatch into nymphs.


Squash bugs must be controlled at seedling stage and when plants start flowering. Check for egg masses on the underside of the leaves and spray with insecticides recommended in your state when they are at nymph stage. In small gardens, use row covers and physical destruction of the egg masses on the leaves before they hatch.


squash bug

squash bug

squash bug