Prevention is the key to squash vine borer management. There are no good control alternatives once borers have entered the vines. Poor timing of sprays or inadequate spray coverage are common causes of control failures. Check plants weekly from mid-June through August for initial signs of the borer's sawdust-like waste (frass) that is ejected from holes in the stems. Very early signs of larval feeding indicate that other eggs will be hatching soon. Use two insecticide applications, 7 days apart, to control newly hatching larvae and continue to monitor for additional activity. Sprays need to penetrate the canopy and cover the vines to be effective. Contact your local Extension office for insecticide recommendations.
Home gardeners may have some success with removing worms from limited numbers of infested vines. At the first signs of sawdust-like waste material coming from a vine, split it lengthwise near where the damage is found and remove the borers. Then, immediately cover the stems with soil. Burying a few nodes along each vine will encourage rooting and can lessen the impact of borers that girdle the base of the vine.
Sanitation is an important step in long-term control. Remove vines and compost them after harvest is complete. This will prevent the remaining borers from completing larval development and surviving to cause problems next year.
