Browntail Moth Caterpillars Are Cocooning (July). GOOD NEWS, the cold wet spring appears to have encouraged deadly fungus and bacteria to decimate many winter webs in our area. The active population is much smaller than expected.
We have not seen nearly as many active caterpillars in May/June as was expected from the number of winter webs in trees: it looks like fungus and bacteria encouraged by our cold wet spring have done us a huge favor. There are localized areas of infestation, and the pests could make a comeback, but overall Georgetown’s colony appears to have substantially collapsed. Hairs in the environment are toxic for three years: you may still experience a rash from this year’s or previous year’s caterpillars. The white moths will be laying their egg masses on the undersides of leaves in July/August. Removing egg masses is also a good way to control future populations: look on the undersides of leaves. Once those egg masses hatch, larval caterpillars will be feeding (defoliating leaves) and constructing winter webs through August and September.
Maine Dept of Agriculture, Conservation and Forestry published this excellent FAQ sheet:
For a lot more information on browntail moths in Georgetown, click here Browntail Moth
DACF 2019 risk map is on the right: red indicates severe infestation areas, cross-hatching shows observed defoliation from aerial surveying including Georgetown.