Question
I have a water oak tree which is about 20 years old and appears to be healthy except for leaves new branches at the top of the tree which have been stripped of their leaves. Can the insect eating the leaves kill the tree?  How do I get rid of them?  Thank you.

Answer
No generally insects that defoliate a tree will only cause growth loss unless the tree is stripped of its leaves for several years in a row and then the tree will get some branch dieback but not be killed by the leaf feeders. More than likely the insect that has eaten the leaves has completed its life cycle and will do no more damage this year. To protect the tree next year i would treat the tree with Bayer Advanced Tree and Shrub Insect Control. This insecticide is applied to the soil around the tree and the roots will carry it to the leaves and twigs and when the insects feed they are killed. Apply his next spring and it will protect the tree all the growing season. Using it now will not work well since soon the tree will shut down for the winter and stop moving water up the tree to the leaves. Check with your local garden type store for this product.