There are several good books you could get to help you ID the caterpillars you find. One is Caterpillars in the Field and Garden which is a field guide to the butterfly caterpillars of North America by Allen, Brock and Glassberg. Once you learn what your local butterfly caterpillars look like, then at least you'll know not to squish them. If you're in the east, another good book is Caterpillars of Eastern North America by David Wagner - this is mostly moth caterpillars. I'm sure you'd want to save any big silk moth and most sphinx moth cats. Then everything that's left is probably a pest, especially if it's tent caterpillars. I'm glad that yellow-billed cuckoos show up here every year just when the outbreak of tent cats is beginning! Another helpful book is Garden Insects of North America by Cranshaw - this book IDs a lot of butterfly and moth caterpillars, plue other larvae like sawflies that eat leaves. Another way is to take a picture of the offending leaf eater and post it on this forum - we may (or may not) know what it is. I don't blame you for wanting to protect your serviceberry. I've got a young amelanchier arborea that I just love - so far, no cats have found it. I figure the only ones I'd be likely to find on it would be either red-spotted purple cats or tiger swallotail cats, and I wouldn't mind having them - these two butterflies lay their eggs far apart, so no plant gets really ravaged by either of them. MissSherry

But I know exactly how you feel because a number of years ago I lost almost every Anise Swallowtail butterfly cat to a parasite that would kill the cat usually within the first or second instar, probably the second, in the same way. I would watch the cat feed normally for a while and then it would stop eating and just sit motionless for days and then one day it would be still sitting on the stem but looking sort of shrivelled up and there nearby would be a tiny beige cocoon. It would not have bothered me so much had it not taken all but one cat over an entire season. I almost gave up on the butterfly stuff after that season. Unfortunately, I live in a somewhat agricultural environment so there is not much one can do if people decide to import preditory insects to control what they consider pests. The worst part of the experience was that the cats had come from a number of places in my area and had nevertheless managed to come in contact with the same parasites. For awhile I feared that the Anise Swallowtails might never survive or that the other butterflies would be killed off also. Thank God I was wrong. I have not had the problem since. I don't know what to say beyond that except that I am not capable of being neutral about the whole food chain thing. It is what it is. Murray

I have never seen Eastern Tentworm Caterpillars go to the roses so this probably is a moot question, but if it is absoultely necessary the BTK is a good protectant. Sevin is not an organicaly acceptable product and should not be mentioned on an organic forum. The Cornell spray is a fungicide rather than an insecticide and I've not seen it to be effective against aphids or spider mites except if the pressure it is applied with is high enough (should not be) to knock the aphids off the plant although the higher humidity of applying it may discourage the spider mites.

You might have better/faster results using google. Unlikely your girlfriend was intentionally injured but the hairs on many caterpillars can be irritating when they get into the skin.