One of the most devastating pest problems I've ever had in my garden was an infestation by the evil squash vine borer. I'd never grown squash before. It was 2009, and even though I'd heard all the complaints of gardeners with such bumper zucchini crops they had trouble getting rid of it all, I just had to try growing it myself. Truth be told, I don't even care for zucchini, but as gardeners we often grow stuff for the sport of it.
Adult squash vine borers emerge from cocoons in the ground in late June to early July. Then, these wasp-like moths lay eggs at the base of the plant and about a week later the eggs hatch and the larvae bore into the stems of the plants to feed. A zucchini plant infected with squash vine borer is a horrific sight. The larvae in the stems block the flow of the water to the plant and the base of the plant rots, turning yellow or brown while the big beautiful green leaves struggle to stay alive. It was like watching a sick animal die a slow death. I overwatered to keep them alive and that worked for a while. But during my infestation I did some research to explore ways to cure my ailing zucchini and found several references to cutting the base of the stem open and physically removing the larvae with tweezers. Like zucchini surgery. I tried, but the sight of those worms nestled right in the middle of the stem was too much. My gag reflex eventually won and I yanked out all the zucchini plants vowing never to grow them again. But alas, as a gardener it is hard to admit that a plant has won.
Considering the life cycle of the squash vine borer, the solution seems pretty simple. Plant them after early July when the adults have already emerged and found somebody else's plants to lay their eggs on. Zucchini grows so fast that directly sowing the seeds in early to middle July should still allow plenty time for the plants to produce enough zucchini to eat and share. I wish I could take credit for coming up with this idea myself, but it was actually suggested last year on a local gardening radio show I listen to every Sunday. I've had three years to get over the squash vine borer trauma and I'm ready to give it another shot in 2012. I'll keep you posted!