Squash vine borers are native to the eastern US, and by this time of the year, they’re munching on our plants and causing damage. Squash vine borers are different from squash bugs, by the way.
The telltale signs of an infected plant: rotten stem, sawdust-like substance, and/or wilting leaves. Check the base of the stem. If it looks rotten or hollow or you see a sawdust-like substance, act quickly. If your squash leaves are also wilting, it might be too late to save the plant.
The adult moth resembles a wasp, and here in Georgia, has two broods a year, laying its eggs at the base of the stem. The egg hatches and then the larvae bores itself into the stem. The sawdust-like substance is actually waste from the larvae. The larvae, after doing a number to your squash vine, burrows itself into the soil and pupates the next spring, restarting the cycle.
Larvae
Adult Moth
How to save an infected plant: Slit the stem with a sharp knife and pull the larvae out. Cover the damaged area with plenty of soil to encourage root growth and keep it moist. With a little luck, the squash plant will perk up.
What to do with the larvae: Squish the sucker, but if you can’t stomach that, drop it inside a birdhouse. If you drop it into the soil, it will overwinter and pupate next year.
How to discourage squash vine borers:
- Till the soil to expose overwintered larvae.
- Rotate crops.
- Wrap the base of the stem with pantyhose or foil to prevent egg laying.
Further reading:
- Clemson Extension (Disregard any non-organic recommendations! But they have great pictures and descriptions.)
- ATTRA (Organic recommendations!)
