Squash vine borers are moths that lay eggs on the base of the squash plant. The larvae then tunnel into the plants and cause them to wilt, collapse or die. This segment discusses how to identify squash vine borers, and how to treat your plants to prevent damage.

Produced by the Department of Communications at Kansas State University. For more information, visit our website at: http://www.kansasgreenyards.org

Squash Vine Borers

One of the biggest problems that you may see this summer with your squash plant is the squash vine borer. It causes squash plants to wilt and die just as it’s reaching productivity. If you look closely at the plant, you’ll see a brown area – possibly with holes around the stem – where the caterpillars have bored into the stalk of the plant. They are chewing their way up the plant and depriving the plant of water and nutrients. This causes wilting and the ultimate death of the plant.

A squash vine borer is actually a moth that lays eggs on the base of the squash plant, near the soil. This usually happens in late May to early June and into mid June for northern parts of Kansas. The best way to prevent squash vine borer damage is to be watching for the moths flying in the garden. It’s an ugly black and red moth that you may see flying near your squash plants.

You’ll need to scout around the base of your plant to look for squash vine borer eggs. These eggs are tiny, dull, reddish-brown ovals on the base of the plant near the level of the soil. Then, once you’ve seen those two signs, you’ll need to use an insecticide or a barrier to prevent the caterpillars from boring into the plant, or to prevent the moths from laying eggs on the plant.

When you look at insectides, you can use insecticides such as Pyrethrum, or Esfenvalerate. Either one is very effective. And, Rotenone, as an organic option, may be effective. You’ll need to make sure that you thoroughly spray the base of the plant, especially the stalks and vines, every seven to ten days while the squash vine borers are flying around and laying eggs.

This feature story prepared with Rebecca McMahon, Kansas State University Research and Extension Horticulture Agent, Sedgwick County. For more information, visit your local county extension office or visit our website at KansasGreenYards.org.

Horticulture Newsletter

KSU Horticulture Newsletter

Get more information from our weekly newsletter.

Find Your Local Office

Have questions or need help?

Local Extension Office Map

Click the map to find your Local Extension Office.

YouTube Videos

YouTube Videos

Watch K-State Research and Extension Videos.

Kansas Healthy Yards Tagline