In our first growing year we grew an abundance of winter squash. It was so easy to amass this large quanity of storage fruits for the winter. The second and third year proved to be a big disappointment as we were invaded by the nasty squash vine borer (SVB). It attacks plants as a moth laying eggs at the base of leaf stalks. The larvae then develop into these gross looking light green catepillars that burrow themselves into the healthy large stems of squash plants. The first sign that something is wrong is the the appearance of wilting leaves. It looks like you forgot to water your patch of squash. Upon closer inspection of the base of the main stem you will find your stems gouged open with several SVBs inside happily munching away and slowly killing your plant the many young fruits attached to the vines. I have literally picked these bugs out and tortured them on a nearby rock. They have killed off so many of my squash crops that I've taken it personally. After removing the pests, it is possible to bury the damaged area in the soil and it will reroot but I've never been able to keep up with it and eventually give up losing the patch.
This year we are trying something else: using a row cover to prevent the moth from laying its eggs at the base of the stalk. After planting a variety of winter squash: red kuri, buttercup, butternut and delicata we set a floating row cover on all the plants. It's mid June and this is the time the SVB moth starts egg laying. If you do get this nasty pest, remember not to compost the vines at the end of the season but to throw them out in the garbage.
We're not the only ones doing this. This is a squash field at Stone Barns in Pocantico Hills, New York, also covered with a row cover. We are wondering weather or not this is going to present a problem with pollination, however. Our squash just started to flower... Another experiment we'll report back with.