Lilacs under attack by yellow hornets
For years I have watched large yellow hornets scrap/eat the bark of my lilac trees. The hornets remove the bark in bands around the limbs and consequently the lilac suffers. I believe this happens in the late summer and is going on now . I can see a dozen yellow hornets at any time on my lilac. Two questions; what kind of hornet is this? How can I help my lilac tree? If this is more of an bee/insect question please let me know.
There are no products registered to prevent European hornets from girdling the twigs or bark. They are looking to feed on the sap. All you can do is prune dead or damaged wood. Lilacs can benefit from pruning as this lets more air and light into the center of the plant. See our website for more information http://extension.umd.edu/hgic/european-hornets