Squash Vine Borer

Squash is a popular garden vegetable. One or two plants can easily produce as much or more squash than a family can eat. This has spawned a host of recipes that use squash in every dish imaginable. The summer burst of squash usually lasts for only a couple of months until the squash plants finally succumb to disease, usually bacterial wilt that is transmitted by the tiny cucumber beetles or corn rootworm beetles.

There are some larger pests that can lay low a squash plant including squash vine borer. The squash vine borer is a day flying moth with clear wings. It superficially resembles a wasp. Its mimicry deters predation by birds. The moths lay eggs on the stems of squash plants just above the soil line. The eggs hatch and caterpillars will burrow into the stem to feed. The caterpillars are not visible from the outside, but they produce a sawdust-like frass (excrement) that collects on the outside of infested stems. It is possible to kill a larva by poking through the stem and in some cases it can be removed without killing the plant by carefully slitting the stem until the larva can be reached and extracted

Initially, squash vine borer only stresses the plant without killing the it. Sometimes the squash vine borer can complete its development without killing the plant, but sufficient damage will kill the plant. Once the larvae reach maximum size, they will leave the stem and burrow into the soil to pupate. In Indiana, squash vine borer spends the winter in the pupa stage to emerge and infest plants once again the following summer.

Top: Squash Vine Borers Tunnel and Feed in Squash Stem
Bottom: Caterpillar Extracted from a Stem

About jjneal

Jonathan Neal is a retired Associate Professor of Entomology at Purdue University and author of the textbook, Living With Insects (2010). This blog is a forum to communicate about the intersection of insects with people and policy. This is a personal blog. The opinions and materials posted here are those of the author and are in no way connected with those of my employer.
This entry was posted in Environment, Pest Management, Policy. Bookmark the permalink.

2 Responses to Squash Vine Borer

  1. Pingback: Clearwing Moths | Living With Insects Blog

  2. Pingback: Living With Squash Vine Borer | Living With Insects Blog

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