Squash Vine Borer

What it looks like

Adult squash vine borers are clearwing moths that fly by day and look like wasps, with metallic green front wings and a bright orange body with black dots. The caterpillars are white with a brown head.

The adults lay eggs at the base of squash, pumpkin, and zucchini plants. The caterpillars tunnel into the stem, then leave the plant to spend the winter in cocoons in the soil. Adults come out in May in the South and late June to July in the North.

Damage

The caterpillars tunnel into the stem near the soil line, cutting off water to the plant. The first sign is often a plant that suddenly wilts, with a small hole and sawdust-like droppings at the base of the stem. Several caterpillars can kill a plant.

How nematodes help

The beneficial nematodes in BioLogic's products attack the young caterpillars at the base of the stem. In field trials, nematodes sprayed on the stem base and the soil around it sometimes worked as well as an insecticide. Results vary from year to year, and timing matters: applications after the caterpillars are deep inside the stems don't work.

How to apply

Treat with Scanmask from May through July, starting as soon as the adults are flying and the caterpillars hatch.

Spray the base of the stems and the soil around the base of the vines.

See How to apply for step-by-step directions, or use the calculator on the Scanmask Spray page to see how much you need.