Red Twig Dogwood Leaves being clipped and falling off
I have three Red Osier Dogwood bushes in my backyard that I planted about 3 years ago. They are all under big fir trees and are basically in a dry shade environment. They are all placed about 3-4 feet apart and are still relatively small (3-4 ft high).
This spring, I noticed the leaves falling off of one of the bushes. When I looked more closely, it looks like the main vein of the leaf is being clipped/chewed through right at the base of the leaf where it goes into the stem. The leaf then wilts and falls off. It was only happening to one bush but now it is happening on all three.
I see no signs of pests but I have noticed some very light webbing on them as well as a few VERY small bugs (can only be seen with a loop) that are silverish and don't seem to have wings. I didn't get a photo because they are just too small.
Any ideas on what could be the problem? Thank you!
Multnomah County Oregon