I'm in Garland, and the SVB are real bad here in my neighborhood.

Have you tried a row cover? I use cheap tulle fabric, bought a big bolt of it last year and still use it. (108" wide) I cover my plants from seedlings till their first female flower open, and it really helps extend their life.
Once I remove the covers, I will monitor the plants every few days and pick off eggs. Some do fall in the dirt. When that happens, I just stir the dirt a little and pile some more mulch around the area. I doubt the tiny larva would be able to dig their way out and find the plant.

Oh yeah, the SVB are around for a LONG TIME. Ive found them around until mid-Oct.
So really, your best bets are starting your plants really early in the spring, and protecting them from the frost when tiny, or starting later and depending on the row covers. Or if you start in the fall, covering them until Oct.

Good to know, thanks. I haven't tried the row covers because I did not even know about SVBs until I already had them - luckily I've only lost 2 small seedlings since they showed up, still have plenty of squash plants going strong...but I imagine I can only get away with surgery on them so many times in a given season - at some point that's going to take a toll. I've sent away for some of that stuff people say you can inject into the vine to kill the little maggots before they begin doing real damage. Hopefully it'll arrive soon.

Here is what I do also.... I have a syringe I got from a printer cartridge refill kit. I inject BT solution into the stems when I see any signs of damage. One of the best indicators of damage is when vines start looking swollen and start yellowing. Obviously frass is another sign. (but that almost a bit too late)

Instead of cutting the plant a lot and causing it much damage, I do this (I saw this on Youtube) : When you see frass, or when you see a swollen yellowing part of the vine (that also indicates they are in there). Then open a small hole in the vine with a small knife... pretty small no bigger than a pencil. If frass is coming out then the hole is already there but you might try to make it slightly larger. Then inject some soap solution (water and ivory soap mixture). I have done it with my needle, but saw a guy use a spray bottle on "jet" mode, and spray it up the hole. The borer will either be forced to come out of the hole, where you can kill it, or the soap will kill it.

Have you ever injected the BT into the vine before seeing any signs - as a preventative?

Last year I injected diluted Neem oil into the affected stem. I don't know if it killed the larvae or made them leave but the plants survived after that and produced. I assume Neem oil is not harmful in the food chain either.

I don't really have anything positive to add here. It is my second year of vegetable gardening and the SVB destroyed my plants before I knew what was happening. Still much to learn and my zucchini squash has fallen victim again to the SVB. At least this time I got to cut open the stem and kill the little worms before I decided to compost the whole thing and start over. Will definitely try to cover my plants and treat with insecticidal soap and Bt now!

Every failure is an opportunity to learn!

While useing a cover,must you repeatedly remove the cover and hand pollinate? I was born and raised near Paris Tx and never heard of a svb until moving close to the DFW area. That is less than 75 miles difference but soil near Red River is red clay,sand mix while Southern Collin county is black clay. I'm curious if those of you in East Tx have as much damage from svb as those in the Blackland prairie.

Yeah you have to, or just remove the cover and at that point, you probably have at least three weeks of production until your plants start showing damage.