We noticed over the weekend that several more of our hemlocks are doing the same thing.

Asked August 25, 2020, 4:03 PM EDT

About 30-35 years ago we planted a small Hemlock on the edge of our yard and it has grown into a beautiful tree. We just noticed that several areas have yellow and/or brown areas on the needles. We did not notice any woolly adelgid in the spring, but it is possible. We would like to save this tree. Research on the web we determined that if it is woolly agelgid, the only treatment available is Dinotefuran. Please review the photos and advise us what to do to preserve this beauty.

Geauga County Ohio

1 Response

Hello,
After looking at the photo, I do not believe that the yellowing branch is a response due to Hemlock Wooly Adelgid (HWA) feeding. Rarely does the adelgid just affect just one single branch but usually affects and area of the tree. Because of the adelgid's small size, one of the best ways to determine if a hemlock tree is infested with HWA is to look for white cottony egg sacs at the base of the needles. These white cottony egg sacs are present all year, but are just more prominent in early spring. Now, I would examine carefully the new growth to look for the presence of the nymphs of the HWA feeding on that growth. If you have any concerns, you can drop off a sample of the plant in question at our office on the Geauga County Fairgrounds. The service window is available and open on Wednesdays from 10am-2pm and leave your information and I can examine it and get back to you.

Hope that helps!