Have had a bunch of questions about dealing with squash vine borers. Here are my 5 ways to deal with them:
- Resistant varieties
You can look for squash vine borer resistant varieties. The only zucchini I grow anymore is Raven, which is a hybrid. It does eventually succumb to the bug pressure, but I at least get a few weeks of zucchini from it before that happens and I take it out. I cannot recommend Black Beauty as it is a real bug magnet.
Southern Exposure Seed Exchange has come varieties you might want to try that are more resistant: for summer squash: Lemon Squash. For winter squash: Green-Striped Cushaw may do well for you. Last year, we did very well with the Upper Ground Sweet Potato Squash (see pic of two Debby grew) which looks like a big tan pumpkin and was a big hit.. that was what was in the photo of me near the end of the presentation. Waltham Butternut is also good at borer resistance and has grown well for me.
- Hand removal
Checking daily, or every other day goes along way! Look at the base of the main stem, about 4” from the ground up.
If you see a bulge in the stem, there is likely a squash vine borer worm in that bulge.
To remove the worm:
- make a vertical slit, along the stem:
- carefully open the stem to find the worm
- remove the worm and give it a new incarnation
- carefully close the wound and gently wrap it with tape (the tape is optional, but helps the wound heal and keeps out dirt, etc.)
- Crop Rotation
Rotating crops works best if you have a large garden, say at least a couple hundred square feet, or have beds that are on opposite sides of your property. You want to rotate all members of the cucurbit family as one rotation. This includes not only winter and summer squash (and zucchini), but also cucumbers and melons (including watermelons).
If you do not have enough space for this, or if you have a major infestation, don’t grow this family of crops for a year or two. I have done this a couple times with good results and got to experiment with new crops in the meantime.
One organic way to deal with these critters is by adding certain nematodes to your soil. My go-to company for these is Arbico Organics.
- Pheromone Lures & Traps
Another purchased option, again from Arbico Organics, are traps with pheromone lures specifically for squash vine borers.
A Final note is that Blue Hubbard squash is known to be a squash vine borer trap crop. Which admittedly bums us out because we love Blue Hubbard.