Squash Vine Borer

Rick Foster, Department of Entomology, Purdue University

Squash vine borer moths are currently flying and laying their eggs at the base of squash and pumpkin plants. The eggs hatch in 7-10 days and the larvae bore into the stem of the plant. An early sign of squash vine borer feeding is the frass (insect poop) coming from a hole in the stem. Later, the stem or entire plant will wilt and die. Growers should look for the frass to know if treatment is necessary. Your sprays will not control the larvae that are already inside the stem, but it will kill any additional larvae that hatch from eggs. Two insecticide applications spaced 5-7 days apart directed at the base of the plant will control the majority of the newly hatching larvae before they enter the vines. Insecticides containing one of these active ingredients will provide good control: Permethrin, esfenvalerate, and lambda-cyhalothrin. Sevin (carbaryl) will also provide control. Homeowner formulations of these products are available at most garden centers.

Photos courtesy of Cliff Sadof, Department of Entomology

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