What is eating our lilac leaves?
We have established lilacs along our back fence. Tonight we discovered holes all along the edges of the leaves as if pinking shears or a hole punch went crazy around each one. The bushes are 12 to 15 feet high, and the munched-on leaves are in the bottom half, but not so much above. We've looked for caterpillars or some other insect but can't find anything.
It is too difficult to tell from your description. Please send in a picture or bring in a sample to the Colorado State University Cooperative Extension office located on the Boulder County Fairgrounds in Longmont.
This sounds like injury from feeding activity of lilac root weevil, a type of beetle. They are mostly nocturnal feeders. The resulting leaf notching looks like someone used a hole punch to remove a half-circle from leaf edges.
See photos below and the CSU Extension fact sheet at http://www.ext.colostate.edu/pubs/insect/05551.pdf