The following submission was from a neighbor that has had Elm-Leaf Beetle Infestation.
My husband and I live on the 2500 block of South Milwaukee Street. We have a massive Siberian elm in our backyard and we noticed some odd things happening in June, beginning with thousands of small caterpillar-like bugs falling from the tree. We then noticed a shocking number of little yellow and black beetle-like insects which have been subsequently identified by an arborist as the dreaded Elm-Leaf beetle. We remain under siege by these beetles in our backyard. The leaves on the tree do not look healthy as well; they look stressed, yellow-ish and dehydrated. The tree also seems to be dropping an unseasonably large amount of leaves and large chunks of bark.
Colorado State University has an excellent explanation of the Elm-Leaf Beetle at: www.ext.colostate.edu/pubs/insect/05521.html and some treatment recommendations. Apparently these pest pose a serious threat to our trees and like many others, they have discovered our great neighborhood.
We had our tree treated today. Hopefully that will save it. Good luck!