Squash vine borers demolished our very tasty Striata d'Italia summer squash this year. We knew it was doomed a few weeks ago, but I was harboring false hopes of recovery. After a week of increasingly wilted leaves and droopy flowers, we yanked it.
The stem was completely eaten and rotted out and inside it held—surprise!—a couple of big, fat vine borers. These squirmy things eat the plant from the inside out and steal water and nutrients that would otherwise keep the leaves perky and allow new fruit to set. Our extremely prolific Lemon squash is naturally bug-resistant, so it's still doing fine. The cucumbers, melons, and winter squash are also hanging in there, so they are still chugging along in the garden. The vine borers, meanwhile, gave us a nice occasion to have a campfire.