Photo- Chesapeake Bay

Where are they from?

Native to Japan it was brought over to the United States in nursery stock. In the late 1960s it was reported in Pennsylvania.

Why are they so harmful?

Hemlock woolly adelgid causes higher mortality rates in our native Hemlock species, our state tree. This high mortality is caused by the insects feeding on sap from the base of the needles causing the needles to fall off and branches to die-back. Over several years of repeated infestation the hemlock will die. This has caused a disturbance in our ecosystems food chain that has been felt in our birds and other secondary and tertiary consumers (predators).

How can I identify this insect?

They are tiny, white, furry looking insects that will appear at the base of needles of a hemlock. This white mass is the wax produced by female woolly adelgid and will stay even into the winter.

Where can I learn more?

 DCNR --https://www.dcnr.pa.gov/Conservation/ForestsAndTrees/InsectsAndDiseases/HemlockWoollyAdelgid/Pages/default.aspx

Western PA Conservancy -- https://waterlandlife.org/wildlife-pnhp/invasive-and-unwelcomed-species/hemlock-wooly-adelgid/

PSU Extension -- https://extension.psu.edu/hemlock-woolly-adelgid