Photo Credit: G.K. Gerber on bugguide.net
The past two summers, I tried to grow zucchini and squash in my garden; but I harvested very little before the dreaded squash vine borer attacked and killed my plants. People who live here either use pesticides like Seven dust or just give up. Pesticides are not an option in my garden, and this Italian refuses to give up! So, this year I’ve declared an all-out war on the Squash Vine Borer.
WHAT IS THE SQUASH VINE BORER?
The scientific name for the squash vine borer is Melittia cucurbitae. See the word cucurbit in the name? Its very name screams, “I’m going to kill your squash!”
The squash vine borer, or SVB, is a moth that lays its eggs at the base of squash vine stalks. When the eggs hatch, the caterpillars burrow into the stalk and eat the inside of the vine – thus, killing it.
The larvae then burrow into the soil, wrapped in a cocoon. Here in the South, the first generation (we get two – aren’t we lucky?) emerges as moths in late spring/early summer, usually around late May, and lay their eggs on the squash. And the cycle begins again.
After two years without getting oodles of squash for all my summertime recipes, I’d had enough. So, I did some research on how to combat this fiendish pest.
HOW TO COMBAT THE SQUASH VINE BORER
1. CROP ROTATION: Because the SVB cocoons in the soil, crop rotation is a must. It can’t stop the adults from laying eggs on your squash that’s elsewhere in the garden, but why serve up a meal to them on a silver platter? I rotate all my crops every year, so this wasn’t a new thing for me to try.
2. ROW COVERS: If you cover your squash during the time that the adult SVB is looking to lay her eggs, she can’t get to your squash. However, you will have to remove the cover when the female flowers bloom or hand-fertilize your squash. With my schedule, that’s not an option for me.
3. CHOOSE RESISTANT SQUASH: Squash is part of the cucurbit family, but there are more than one species of squash. The four most common species are C. pepo, C. moschata, C. maxima, and C. mixta. Of all the species, C. moschata is the most resistant to the squash vine borer. Unfortunately, most summer squash is of the C. pepo species. However, I did find an Italian variety of squash that is C. moschata – Tromboncino squash! All but one of my squash varieties are from the C. moschata species this year: Tromboncino, Burpee’s Butterbush, White Acorn, Black Futsu, and Seminole pumpkin. I do have one C. pepo variety – Tondo Scuro di Piacenza – which is a round zucchini. It’ll be interesting to see how vulnerable it is compared to the other squash.
4. PLANT EARLY OR LATE: The goal is to not have a meal of squash ready to go when the SVB is ready to lay its eggs. I chose to plant “early” by planting transplants rather than direct sowing. I just added seeds to my germination station, and they grew quickly. In fact, many of the squash produced male flowers before I even transplanted it!
You can also plant later in the season, after the SVB lays its eggs, so it misses your crop altogether. (I’ll have a fall crop planted in August, yet then I’ll be battling pickle worms and powdery and downy mildew. But I digress.)
5. PROTECT THE SQUASH VINE STALKS WITH COLLARS: I read that putting collars around the base of the squash vines helps prevent the adult SVB from being able to lay her eggs there. I also read that the color silver disorients insects, confusing them as to what they’re seeing. So, I combined those two facts and made collars for my squash and pumpkin out of heavy duty aluminum foil, shiny side out. I folded the piece in half, then in thirds to make a three-inch wide strip. I pulled the soil away from the base of the plant and wrapped the foil around the stalk, loosely enough to let the plant continue growing. I then put the soil back around the base of the collar. I’m not sure if I did it correctly, but we’re going to find out soon enough.
Even the tromboncino squash in the pot under the teepee trellis got collars.
As you can see, my squash are dressed for battle, and I’m determined to see that they win! I’ll keep everyone posted as to how the war goes.
If you’d like to read more information on fighting the war against the SVB and other squash bugs, see “Squash Bug and Squash Vine Borer: Organic Controls.”
Do you have the squash vine borer where you live? How do you fight it?