From: "Christopher Fuhrman"
Hi,

snip

Question: will they take care of saw-fly larvae? My observation is that they
seem to flee them, as they flick their tails at them...

This is a typical action for them. That is how they discourage predators. Good
news is, yes there are predators. Bad news, ants and stink bugs lol. Also,
paper wasps will patrol constantly to find them, and love them. Although
Bacillus thuringiensis will affect some fly larvae, I didn't see the saw fly
listed. It turns out that BTK will only work on catepillars, and sawfly is not
a catepillar. You can get it at your local nursery, along with horticultural
oil and insecticidal soap. This site has a lot of info on roses
http://members.tripod.com/buggyrose/...esawflies.html

This is my biggest
frustration with my roses, as I don't want to use pesticides. I end up
picking them off by hand, or cutting the new growth once it shows signs of
laid eggs (trauma to the fine branches). It's tedious, and I wish there were
some natural predator to take care of that for me.
GC
Certified Square Foot Gardening Instructor
http://www.squarefootslo.com
Learn to be a freelance web designer http://www.howtofreelance.com