Quote:
Originally Posted by gorbelly
I think crop rotation is really just the issue when you want to use a row cover strategy, right? Because if you don't rotate, you risk having moths hatching from pupae in the soil and mating and laying eggs anyway despite the trouble you've gone through to cover and hand-pollinate your squash.
Right. But from our point of view, it's easy to miss tiny bore holes, and it seems like the plant is a goner overnight. Even diligent and experienced gardeners experience the heartbreak of walking out one morning and realizing that the borers killed one of the plants that looked 100% fine the day before. It's not like a pest that takes down plants by defoliation.
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This is true but I roto till once a year in the Fall which hopefully exposes the pupae to bird predation and death from the cold in the winter months. I tried row covers one year and still got SVB so now I use the bt as a preventative and it seems to work better for me. I also had trouble with row covers because the zucchini plants got so big that they created gaps in the covers and that is probably how the moths got inside and infected them. I had grown a parthenogenic variety that does not require insect pollination so I did not open the row covers to hand pollinate.
Yes, it definitely seems like an overnight event to us but according to PA State entomologists the larvae feed for 4 weeks before killing the plant. This is probably why I have good luck with injecting the bt into the stems before I even see any damage. if you wait until you see the damage, then it will probably be too late. I know that they will infect my plants so I inject the bt as a preventative. It is the only way I feel confident that I will have zucchini.
http://ento.psu.edu/extension/factsh...ash-vine-borer