Question
I have a lot of Elm trees and they all have little holes in the leaves, I had to cut one down because it became so weak and the branches were breaking off and damaging my house, but the tree co. said it was damaged from squirrels. But now I found two trees at my other house that transplanted there from some soil I had moved over there from around the holey trees and they are both about 20 ft. tall now and we like them but I don't know what the holes are everywhere and I don't see anybugs anywhere.

Answer
Hi Lori,

It sounds like your leaves are being fed on by elm leaf beetles.  It is not uncommon not to see the insects and to only notice the damage.  Since you are in Colorado, this is a link to a fact sheet about these beetles from Colorado State University Extension.  It includes information about the elm leaf beetle and control options.

http://www.ext.colostate.edu/pubs/insect/05521.html

Good luck,
Jen