I read all of last years Questions and replies pertaining to the dreaded "Squash Vine Borer". I would give odds that most of your leaves that collapsed after mid-August had a Borer in the lower 6 inches of the leaf stem and the borer had already exited. In my area borers are only in the vine 5 to 6 weeks. I doubt that burning vines in October does any good because the borers are in the ground by then.

Here is what a College Biology Professor told me about 15 years ago and I believe its all true. In this area the Adults begin to emerge from the soil from mid-June to July 1, depending on May and June temperatures. The adults DON’T EAT so insecticides won’t harm them. They are energized by the SUN. Early in the morning and late evening you may find them on top of leaves and logy (I carry a fly swatter in a belt loop and sacrifice leaves to kill them). About one hour after sunrise, if you get close to one, its gone. They are very fast flyers... The females mate, lay 80 to 100 eggs and die in 2 or 3 days. The males also die 2 to 3 days after mating with one or more females.

The eggs hatch in 5 to 7 days. The borer eats its way into the spot where the egg was. In 5 to 6 weeks it will be about 3/4ths inch long and exits into the soil until the following year...I do not believe there are 2 generations per year in my area. In a year with warm early weather I see adults starting mid-June and a few to the end of July. I see the highest number about 2 weeks after the first one. Last year May and June were cold and I saw the first one June 30, but not many until mid-July and some were around until August 20. When they emerge depends on the soil temperature and how deep they were in the soil. In years that they show up late I find borers, or where borers had been, in up to 10% of my Jack-O-lantern pumpkins that I begin picking in mid-September. Last year they ruined about 1 out of 4 of my "Munchkins".

In 2000, I used "Admire" (Systemic) on my AG's and 7 Burpee Prizewinner plants and it's the first time I didn't have a collapsed leaf from borers. See my article titled Systemic Insecticide use in 2000. The only undesirable feature is you will kill bees (and you don't want to do that) unless you remove ALL unwanted male and female flowers at sunrise or on previous days.