re: Pine Beatles...Maybe?

You can try spraying but I really don't think it will do any good. The adults have already migrated from the first tree and if they landed in some of your other trees they've already laid their eggs, and it's not possible to get an insecticide under the bark where the eggs and larvae are. Insecticides have never worked effectively on bark beetles. To protect a tree you would have to soak it from top to bottom to repeal the adults as they migrate to a new tree to mate and lay eggs. I'm sorry...

One poster said bark beetles start at the top of a tree. Not so. Each species of bark beetle tend to start at a different height on a tree, but a tree dies from the top down due to the lack of moisture and nutrients hits the top first. Once the top starts turning the tree is dead and doesn't know it yet