Squash Vine Borer

Had your squash plants been doing really well, but all of the sudden they started to struggle? The squash vine borer might be to blame. The squash vine borer is a type of moth that lays its eggs at the base of squash plants.

When the eggs begin to hatch, the larvae burrow, or bore, into the stems of the plants, weakening them significantly. The borers overwinter in the soil as pupae. This pest is particularly prevalent throughout the eastern United States, and predominantly attack squash and zucchini, however, they can also attack pumpkins and gourds.

Borers start to hatch in early-to-mid summer, within one to two weeks of being laid. They then bore into the stems for several weeks to feed. If spotted before the eggs hatch, it is possible to prevent damage to the plant, however, if caught after the eggs hatch, it might be too late.

There are a few signs of squash vine borer damage, with the first sign being inexplicable wilting of the plant’s leaves. You might also see holes at the bottom of the plant stems or what appears to be sawdust at the base of the plant. This is the chewed-up stem that the borer produces as it burrows farther into the plant. The site of first feeding will appear rotten first.

As with most pests, prevention is key to preventing damage. The best method of prevention is to plant squash plants in different areas each year, which starves the overwintered borers that are at the site of last year’s plantings. You can also use row covers until the flowers appear on the pests, allowing your plant to have a head start ahead of the pests.

Should you discover that you have an infestation of squash vine borers, quick action is needed to minimize the damage they do to your crops. You can try trapping the adult moths, which are most active at twilight, with yellow sticky traps. You can also apply a pesticide with the active ingredient of Bacillus thuringiensis v. kustaki (Bt), permethrin or carbaryl. While these are safe for use on squash plants, it is important to read the labels prior to application.

The Essex County Co-Op sells Bt, Sevin, and permethrin, all of which can be used on your squash plants. Unsure of what is ailing your squash plants or how to help them? Come see us!