Squash vine borers are killing our zuccinni, summer and buttercup squash! We probably discovered this too late, but we wanted to share with you what we’ve learned.
So here’s what we’ve discovered:
Squash vine borers lay eggs at the base of the plants, which upon hatching bore into the stems to feed. They live inside of the stems preventing water from reaching the rest of the plant. After feeding for about four weeks, they leave the vine and bury themselves one or two inches underground until next summer.
Symptoms of the borer include wilting plants, holes and a moist sawdust-like material at the base of the plant.
These pests are difficult to manage once present in the crop. One way to prevent the moths from laying eggs on the plant is to wrap the base of the stem with aluminum foil or nylon stockings. Also, covering the plant with row coverings until bloom can protect it from the borer. Companion planting with repellant plants—catnip, tansy, radishes, nasturtiums, or marigolds, beebalm, or mints is also helpful.
Once the squash vine borers dig in, there are a few options for saving your plants. Physically removing the maggots from the stems is one way. Once you have killed any borers with the tip of a knife, mound moist soil over the cut area and keep this spot well watered. New roots may grow along the cut stem, allowing the plant to survive. Bacillus thuringiensis, or bT (a naturally occurring bacterium common in many soils around the world) can also be sprayed on the plants.