A few ideas – maybe too kumbaya for you but FWIW : )
First, it helps to know the enemy. This video is great because it shows a female adult laying the single eggs, and greater because the guy planted radishes around the squash (supposedly a deterrent – NOT!). Ignore the fact that the narrator says “HE is trying to lay eggs…”
If you are willing to search and destroy the eggs, both the borers and the squash bugs have copper colored eggs that they will lay on the back of leaves or o stems (the bugs lay egg masses; the borer lays single tiny eggs.) I watched a youtube video where the woman wrapped some duct tape in a loop around her hand backwards, touched the eggs and picked them up off the back of leaves and stems that way.
How often? This data sheet from U of Minnesota says the eggs hatch in about a week, so I’m thinking that checking for them a couple of times a week probably would keep on top of them before hatch.
Interesting idea to use a yellow bowl of water to attract and drown the adults. I’m going to try that.
I am using Bt, a biological control. Some people shoot Bt into the stems when the borers are present and try to nuke them that way (I tried on an already infested zucchini plant – seemed to help - less involved than cutting the stem open). It’s toxic for bees and butterflies, so spraying in the evening when they are less active is recommended.
Yes, apparently the tulle (wedding veil netting) tied around the stems can be very helpful, but the borers also will lay eggs other places so may not be sufficient. You can cover the plants with row cover fabric till they blossom and then uncover a couple hours a day, BUT if there are already borer larvae in the soil from past problems, this will not work. I hear it helps to turn over the soil early in the season to try to reveal the larvae that overwinter for the birds’ benefit.
If the problem is really severe and you want to try an alternative, I read about a taste test that compared winter squash types harvested prematurely as a substitute for zucchini or summer squash (I think it was Southern Exposure Seed Exchange). The winner was a winter squash named Seminole, same type of squash as butternut (C. moschata, which I agree is highly resistant to borers), apparently tastes sweeter than zucchini when harvested immature as a summer squash and people liked it best. I just grew out some Seminole seeds and am trying it for the first time this year. Tatume, a Mexican vining squash, is supposedly less susceptible too. I tried it once – didn’t really love it, but am growing it out again to retry this year.
Good luck to us all combating this dreadful pest!