I just read in the latest issue of The Avant Gardener that there is a new pest moving into the NE - the winter moth. The caterpillars from last year's crop should be hatching out now. The scientific name is Operophthora brumata. It originated in Europe, moved into Canada a few years ago, then into the PNW and is moving into New England. The article doesn't describe the caterpillar, but does say that the University of Massachusetts says that dormant oil sprays will kill many overwintering eggs, banding trunks with paper and sticky stuff (Tanglefoot, etc.) will get a lot of caterpillars, and Bt, insectival soaps and spinosad will get more. Using all of these, probably more than once, will probably have the most effect, although it's too late for the dormant oil sprays this year. If a tree is defoliated, water it well, apply an organic mulch, but don't fertilize, and it should grow new leaves. 4 years of defoliation can kill a tree. I just hope this pest can't handle the summers in the south, as we have enough pest bugs down here, but I feel for all of you in the NE. And for all my relatives in Vermont, who will be fighting them too! I would think that you could get more information from the UMass website, but Avant Gardener doesn't give an address.

Diggin, I appreciated the photo and the link even though I thought it was grooooooooooss, but now I'm confused, I thought the article eluded to them being tent caterpillers, well what ever those are, they are the ones we have been envaded by. To give those of you who might not know where Otis is an idea, It is situated on the cape between Falmouth and Sandwich. I agree with Chelone that its all part the ecology, however the french guy that brought them here to start with was a loose cannon trying to pass his hobby (a get rich quick scheme in the silk business)as science, He left the country before they exploded into the voracious pest he knew them to be!!! Wendey

They are probably "Genista" caterpillars. It's a moth, and the caterpillars are unlikely to do permanent damage to the trees. Management: No management may be required on mature plants as the worms rarely consume enough foliage to damage the plant. However, young and/or newly installed plants with a small canopy may need to be protected. Handpicking is an effective control in small gardens. Here is a link that might be useful: Sophora Worms

I do not feel as bad now. I ended up with 8 caterpillars which pretty much ate 90% of my milkweed. Another dozen added would have left them all hungry and probably dead. They have all disappeared now which I guess is normal(I did find one on a container about 15 feet away from the milkweed) so I assume in about 2 weeks I will have a pile o butterflies.