Squash Vine Borer - Ask Extension
Hello,
It seems every year I battle squash vine borer in my zucchini. I have tried moving the plants year to year, and some simple traps. What e...
Knowledgebase
Squash Vine Borer #803507
Asked July 28, 2022, 2:16 PM EDT
Hello,
It seems every year I battle squash vine borer in my zucchini. I have tried moving the plants year to year, and some simple traps. What else can I do to prevent them in this area? Does BT do anything? Is it safe to use?
Given the look of my plants they might be gone. I did try to fish out tue larva with a wire on the one that is still.healthy. is it too late to replant zucchini? Or should I not because of eggs in soil? Can I kill those eggs somehow over winter?
Thanks and apologize for all the questions.
Baltimore County Maryland
Expert Response
We offer several options for prevention and management of this pest on our Squash Vine Borer on Vegetables page that might be useful for you. For example, research has shown that injecting stems infested with young borers with Bt (Bacillus thuringiensis, specifically strains aizawai and kurstaki) can control them. These two strains of this naturally-occurring bacterium specifically target caterpillars and shouldn't harm other types of insects or other wildlife. (Different strains of Bt target beetle grubs or fly larvae like mosquitoes.)
If you replant now, you should be able to get a decent late-summer harvest. These moths overwinter in the soil as pupae (not eggs, which are laid on plants directly in May) either in the garden or nearby. After removing the spent plants at the end of the season, you can try using a digging fork (similar to a pitchfork) to loosen the soil to disturb or expose pupae. Push the fork in vertically, wiggle it back and forth a bit to break-up the soil (don't dig it up or flip clods over, though), and pull up the fork and repeat throughout the immediate area. "Uprooted" pupae may then be too uninsulated to survive the winter or can be more easily found and eaten by predators like birds.
Miri
If you replant now, you should be able to get a decent late-summer harvest. These moths overwinter in the soil as pupae (not eggs, which are laid on plants directly in May) either in the garden or nearby. After removing the spent plants at the end of the season, you can try using a digging fork (similar to a pitchfork) to loosen the soil to disturb or expose pupae. Push the fork in vertically, wiggle it back and forth a bit to break-up the soil (don't dig it up or flip clods over, though), and pull up the fork and repeat throughout the immediate area. "Uprooted" pupae may then be too uninsulated to survive the winter or can be more easily found and eaten by predators like birds.
Miri
