When squash vines suddenly collapse, it may be the work of squash vine borers. If you find that borers are at work, surgery for squash vine borers is a last-ditch technique to try save your plants.
Once borers are inside the plants, you have two options: ignore them and harvest what your plant will give you until it finally succumbs (it won’t take long), or go after the rascals with a knife. If you have only a precious few plants, it may pay to try to extract them. To do surgery for squash vine borers, use a small knife to carefully make a cut lengthwise down (not across) the infested part of the stem, as shown at the top of the page. Extract or kill the borers, then bury the cut portion of the stem in the soil.
If you have more than two months left in the growing season, you can also plant another batch of squash and watch them carefully from the beginning.
Of course, the best way to keep squash vine borers from destroying your plants is to stop them from hatching in the first place. Keep a eye out for their eggs — they look like tiny brown seeds and are usually found near the base of the plant. If you see any, remove them immediately, as squash vine borer eggs hatch in a week or less. Chance are they’ll be back, too, so check your plants regularly.
“You know you’re a gardening nerd when . . . you do surgery for borers.”