What I've learned to do in Central Texas is wait them out. I used to plant out in early spring, and by May and June, the squash plants were destroyed. But the life cycle of borers in degree days, for me, is over in June. So I now plant out in May, cover for a month (they're small, so easy to cover), and then throw off the covers entirely in July. My squash plants produce through November. I've heard there may be several generations of borers in a year, but that's never happened for me. Now, up north this won't work, because their life cycle up there isn't over until mid-summer, by which time you only have a couple months of growing season left. Squash plants are large enough that covering for the whole growing season is hard, and once they start producing, you'll have to manually fertilize if still covered.