I've done the squash "surgery," and my plants survived the operation and looked great for a few days. But they were immediately re-infested and dead a week after that. I pulled over a dozen larvae out of two plants when I took them out!
Keeping the plants under carefully sealed row covers from planting and throughout the season works, but you'll have to hand-pollinate. Weekly Bt sprays seem to be effective IF you keep up with them.
I also read recently that you can go out to the garden at night and shine a flashlight through the stems. They're translucent, so you can see where the borers are in the stems. Stab them with a sharp wire to kill them - it does less damage to the plant than slitting it open. You can also inject Bt into the stems to kill borers. The thing is, you have to keep checking every leaf stem in addition to the main stem.
SVBs are bad here, and I am tired of battling them. I am researching Curcurbita moschata varieties to plant next year - maybe Zucchino Rampicante for summer squash. They have solid stems so they resist the borers. But all the moschata squashes seem to make huge vining plants, so figuring out where to put them in my small yard will be tough.
It looks like our plants are pretty well gone. I dont have the physical ability to closely monitor ground level plants, so we might have to forget about growing squash.
Rampicantes are my favorite squash! If you have room for a trellis they can be trained to climb pretty easily, somewhere I have a picture of mine from last year covering an arbor.
They also make a great winter squash. Last year there was one that hid in the leaves near the ground until it was too big to use as a zucchinni. I let it ripen so I could save the seeds. After I harvested it, I also left it on the counter in an out of the way spot so I could get an idea firsthand about it’s keeping properties. It was still solid and fresh-looking 5 months later in February when I cut it open. What’s more, the flesh was so unbelievably sweet that at first I thought someone had dumped sugar in the blender with it when I wasn’t looking! If you use it in a recipe, use only half the sugar - or less - that the recipe calls for, or else it will be overly sweet. Even better, look for recipes that you can taste as you go so you can tailor the amount of sugar, since the sweetness of the squash might vary.
Oh, one more tip, when using rampicantes like zucchinni, peel before cooking. The skin has something in it that turns bitter when cooked. I learned that after ruining a whole batch of soup.