One of the things I have been reminded of and seen in action this year is the importance of timing for pest control.
I have never been able to grow zucchini, because we have so much trouble with the Squash Vine Borer. This year, I wrapped the zucchini stems in tinfoil (just the first few inches above and below ground) and then I grew them under row cover. But early in July, I was leaving on vacation and wouldn't be here to hand pollinate, so I removed the row cover. Came back to find a 9" zucchini that materialized while I was gone! My neighbor just showed me her zucchini that is wilting. I looked and sure enough there was the lesion on the stem, crawling with bugs...
So, hard to know what made the difference, but I'm thinking that by the time I removed the row cover, the adult SVB's were done with the egg laying part of their cycle and had moved on. I'm thinking that if you just protect them through the early season they will be ok. See how the rest of the season goes. They are a little raggedy from groundhog eating the leaves since they were uncovered, but oh well.
Similarly with the JB's. I had a minor outbreak of them for a few weeks, but they seem to be all gone now. I think the adult JB's are only around for a few weeks. If you can protect your crops during that time, that may be all you need to do.
Another piece in learning to garden with nature!