Squash Wilting: Squash Vine Borer (6267)

Squash vine borers are serious pests of vine crops, commonly attacking summer squash, winter squash, and pumpkins. Cucumbers and melons are less frequently affected. In home gardens, entire crops may be lost in a year of high borer populations. Careful examination needs to be made to ensure the symptoms are from vine borers and not from disease.

Beginning in late June or early July, squash vine borer adults emerge from their cocoons. Adult borers are about _ inch_long moths with an orange-and-black striped abdomen and metallic green and clear wings. They resemble wasps when they fly. Eggs are laid at the base of plants. After hatching, larvae bore into stems to feed. Often the first symptom of a borer attack is wilting plants, especially in strong sun. Infested plants eventually collapse and die.

Other common symptoms are holes near the base of the plant filled with moist greenish or orange sawdust-like material. Over time, the base may become mushy or rot away.

CONTROL

Squash vine borers are difficult to prevent. First consider planting vine crops that are usually not attacked by squash vine borers, such as butternut squash, cucumbers, melons, and watermelons.

You can also physically keep adult borers away by placing floating row covers over your crops when they start to vine, or for non-vining varieties about late June or early July. Keep the barriers in place for about two weeks. Do not use floating row covers anytime crops are flowering. This prevents bees from pollinating your vegetables.

Insecticides can help prevent adult borers from laying eggs. Dust the stems at their base with a labeled insecticide. Start treatments when vines begin to run, or for non-vining plants, in late June or early July. Repeat this in 7_10 days. Two applications should manage most squash vine borer adults.

If you discover plants infested with borers, you can try to kill the insects. Use a sharp knife to cut a slit into the affected stem. Slice carefully up the vine until you locate the borers, and kill them with the tip of the knife. Then mound moist soil over the cut area and keep this spot well watered. Sometimes new roots may grow along the cut stem, allowing the plant to survive.

Be sure to promptly remove and destroy any plants killed by squash vine borer to prevent them from moving into the soil for the winter and returning next season.

For more information on this subject, Please visit the College of Agricultural Sciences Publications Web site.

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