After my tough day on Wednesday I started doing some research. These squash vine borers really are nasty little creatures, and not the easiest to prevent. I found some good web pages.
http://www.gardensalive.com/article.asp?ai=804&bhcd2=1243008843http://tomclothier.hort.net/page30.htmlhttp://ohioline.osu.edu/hyg-fact/2000/2153.htmlHere are the main suggestions I've found...
1. use row cover until plant flowers - This one wouldn't have worked this year. By late April I was already harvesting squash, so covering them until they were blooming would have done nothing.
2. Watch for eggs and remove - I planted too many squash plants too close together. There is no way I could have seen anything. Next year I'll create a little more space in between. Now that I have removed several plants (due to death) I can really get in there and have been able to find eggs.
3. Spray / Wipe down plants w/ BTK - I don't know much about this. I've read that it's safe, but would like to talk to The Natural Gardener about it.
4. Plant sacrificial squash - The ohio web site mentions that SVBs like hubbard squash more than other kinds. This would be an interesting experiment to put different types of squash in different areas to see which ones get hit the hardest. Hopefully, the more popular would keep the SVBs away from the less popular ones.
5. Create multiple roots - I like this one too. You bury different sections of the base so they'll generate roots. This way if part of the plant is damaged it's change of survival is higher.
6. Rotate Beds - I already plan on doing this. This is my first year with a garden big enough to rotate. I definitely plan on having the squash in a different location next year. This year was my first time doing summer squash, so I know that the larvae came from eggs, not from overwintering.
7. Succession Planting - Keep planting new squash plants throughout the season. If some get destroyed than you should have seeds going in the ground for the next set. This is a great idea. You harvest all of the squash you can before the SVBs hit and once they do just start over. The family could probably use a break from all of that squash anyway :)
Update ...
I went to the Natural Gardener yesterday afternoon and got one more suggestion.
8. Hand Pollinate
- Keep the row cover on permanently. Instead of having the bees pollinate, do it yourself. At first I thought this was a bad idea, very labor intensive, but after thinking on it a bit I realized it's much less work than slicing open plants and digging out larvae. I may consider this one next year.