Last year the sawfly larvae pretty much decimated my rose bushes. This year I am prepared to fight back. So far I only see the telltale signs on one plant -- a new Chrysler Imperial that I forgot to dormant apray as I picked it up from the nursery after I had already sprayed all of my roses. They are tiny -- I can barely see them. What to do??? Holly
Horticultural oils and insecticidal soaps can be particularly effective at this stage if you get good coverage. Bt will have no effect whatsoever on sawflies. With snow on the ground here in Maine it's amazing to think that people are getting into gardening elsewhere.
Monterey Garden Insect Spray works great. Neem, insecticidal soaps, or other insecticides will not work. Montery has a special compound (spinosad) that controls rose slugs. No other spray I know of has spinosad. I suffered from rose slugs last year and as soon as I found out about this spray and starting using it, the rose slug problem got under control and disappeared completely.
I'll reiterate the response I put in one thread. Beneficial nematodes specific to sawfly larvae. My thrip and rose slug problem disappeared never to come back again when I used it 2 years in a row.
