Q. I have a five or six year old Globe willow tree that is dying limb by limb. I just noticed that some limbs are covered with some kind of beetle that are about the size of my thumb. They do fly and are a little green in color. I did started spraying with Sevin insecticide. Is there something else I can do?
If you don't know what Globe Willow looks like
The one pictured above is 'Navajo' Globe Willow, popular in the Western states.
A. Globe Willow does not have a terribly long lifespan in our climate. If you look around, you don’t see very many old trees.
Borers are quite common in willow in our climate and cause them to have a short life span. The usual symptom of borers in Globe willow are limb dieback, causing the tree to die further and further each year.
Globe willow is disease susceptible. Slime flux disease is a problem it faces and can attract insects that feed on the sour bacterial ooze that comes from infected limbs. In short, I think you are treating a symptom and not the problem.
I do not suspect that these beetles are associated with the borers but, without a picture, I could be wrong. My best suggestion is to remove it and plant a different tree if you plant one at all.