Greetings Angela:
It is the policy of the University of Illinois to encourage landowners and homeowners to first identify the insect in question and to identify the extent of insect damage to your tree(s) prior to pesticide application.
The application of insecticide is not recommended unless the "problem" warrants its use. Can you please identify the insect and the extent of the problem? If you cannot identify the insect, please try to submit a sample or some high quality pictures of the insect and damage to your nearest University of Illinois Extension office.