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Watch your garden for squash vine borers

Jeffrey Hahn, Extension Entomologist

If you are growing squash, pumpkins, cucumbers, or melons in your garden this year, now is a good time to start monitoring for squash vine borers. Squash vine borer larvae bore into the stems, causing plants to wilt and eventually die. The best management is well timed insecticide treatments when adults are active and laying eggs.

Adult squash vine borers are day-time flying moths that resemble wasps. They are about 1/2 inch long with an orange abdomen with black dots. The first pair of wings is an iridescent green while the back pair of wings, which may not always be seen, is clear.

Squash vine borer adult laying eggs.  Photo: Jeff Hahn,
University of  Minnesota Extension
There are a couple of methods for detecting them in your garden. You can watch for them flying around while you are in your garden; they are conspicuous and easily noticed. You can also place yellow containers (like pans or pails) half filled with soapy water. These moths are attracted to yellow; when they fly to the container, they will fall in to the water. It is then an easy matter to check the container for their presence.

As soon as you spot one squash vine borer, start treatment. There are a variety of insecticides that can be applied. If you don’t see any but have a history of these pests in your garden, begin treatment by late June or early July (the further north you are located, the later the moths will emerge).

For more information, including management, see Squash vine borer management in home gardens.
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