The following is from the PA DCNR Bureau of Forestry:
What is the Hemlock Woolly Adelgid?
Adelges tsugae, the hemlock woolly adelgid, is a fluid-feeding insect that feeds on hemlock trees throughout eastern North America, including Pennsylvania. The egg sacs of these insects look like the tips of cotton swabs clinging to the undersides of hemlock branches.
Hemlock woolly adelgid was introduced from Asia into the Pacific Northwest in 1924. It was probably introduced into the northeastern US in the 1950’s, and it was first discovered in Pennsylvania in 1967. This insect has been damaging hemlock ever since, and it is spreading. To date, 47 counties in the eastern two-thirds of PA have been infested with this insect. read more
