Aphids attacking Birch trees?
Hi there. I live 5 miles south of Ninilchik on the Kenai Peninsula and literally in the course of a day or two, every single birch I've looked at on and near my property is covered with these small green bugs. From the small young trees to the teenage ones, I could not find a single one not affected. Alders, even ones right next to the birch have been left alone. I've been taking care of some birch the past few years and I check on them almost daily but I have never seen this happen before. I know Homer recently had an infestation of spruce aphids so it made me wonder if this is something similar?
Kenai Peninsula Borough Alaska trees and shrubs
The species of aphid that target spruce trees are different from the birch aphids. Birch aphids are quite common across the peninsula, and the insects in the photo are indeed birch aphids. Please see the following link for more information on the biology and management of these aphids.
If you have any more questions, please feel free to email me directly.