We live on the edge of Illinois Beach State Park and have masses of gypsy moth caterpillars this year. My hickory tree is rapidly becoming defoliated and the oaks are not looking much better.

Does the state have a handle on this? The village knew nothing except that an arborist told them it is too late to spray. What is the impact of a large outbreak on the 4,000 acres of state land?

Also what can I do?

Response from Dr. James Appleby, Forest Entomologist at the University of Illinois:

Because of limited state and federal funding, I think it will be up to individual homeowners to control the gypsy moth on their own property. Presently I would not try to control the larvae this year as they are now about to stop feeding and begin pupating.

Next year spray Bt (Bacillus thuringiensis sold under the trade name of Dipel or Thuricide) applied to tree foliage after all the overwintering eggs have hatched would give control. Generally that time is around May 10 inland but close to Lake Michigan it may be around May 20.

During drought periods it would be wise to water affected trees that have been severely defoliated.