Experts and BHG readers answer.
What could have caused my squash vines to suddenly wilt and die?
A couple of different insects may have been to blame for the collapse of your squash vines. It is disheartening to have your squash production cut short by infested vines before they produce anything edible. Here are some pest-control tips that should mean you'll be leaving excess squash on your neighbor's doorstep. Squash vine borer. Borers come from the eggs of adult moths. To help prevent the adult moth from laying eggs on your squash plants, grow your plants under floating row covers until after the blooms have begun to appear. Thereafter, closely inspect the base of the vines and stems for single, tiny reddish-brown eggs and wipe them off. If a borer does manage to hatch, you can tell by the appearance of a mass of frass (crumbly borer excrement) on the vine. You'll find the borer entry hole under the frass. Use a small, sharp knife to slit open the vine lengthwise at that point and remove the white larva. Mound soil up around the stem to encourage new rooting.
The plant often survives if you catch the borer soon enough. Squash bug. Squash bugs can do a great deal of damage by sucking juices from the leaves, which then wilt, darken, and die. Watch for a cluster of shiny brown eggs on the top or undersides of leaves, groups of green or powdery gray nymphs with black legs, and 5?8-inch-long dark brown adults with a shield-shape body. Remove each of these and drown or crush them. Soap sprays and chemical controls work on nymphs but not adults. Be sure to clean up plant debris before winter. Plant varieties of squash that are resistant to squash bugs. 'Butternut' is one of the best resistant cultivars.