I've been growing zucchini and summer squash for a couple years now, and every July they start wilting and dying. I've read it's vine borers but I'm not sure how to stop them before they wreck everything. What actually works - netting, insecticide, or should I just plant them later in the season?
The best approach is actually combining a few things - I plant my squash later (like mid-June instead of early May) so they mature after the borers are done laying eggs, and I wrap the base of each plant with aluminum foil or row covers to block the adult moths from laying eggs on the stems! If you're already seeing wilting in July, you can try injecting Bt (Bacillus thuringiensis) into affected stems or just remove the damaged plants and replant a fall crop, which honestly works better than fighting them once they're established.
The combo approach works best - you can't really stop them with netting alone since they lay eggs right at the base of the plant, but wrapping the lower stems with aluminum foil or netting creates a barrier that stops the larvae from boring in. Timing matters too, so are you planting in spring or waiting until mid-summer? If you start later (like June instead of March), the borers might already be in their non-active phase, which could help you dodge them entirely. Some people also do a second planting specifically timed to mature after the borer season peaks. Insecticides work if you catch them early, but honestly once they're inside the vine it's too late, so prevention is really your friend here.
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