Recently people have been noticing large numbers of brown moths fluttering around flowering trees and resting on the sides of homes. These are newly emerged Armyworm Moths. According to Kelly Estes at the Illinois Natural History Survey, these are the moth stage of this spring's larval generation (caterpillars). This spring, Armyworm caterpillars did cause damage in area wheat and hay fields.
Currently these Armyworm moths that are flying around flowering plants and trees feeding on their nectar and pollen, which is the good news. The bad news is that the female moths are laying eggs in grassy areas and these eggs will be hatching in a few weeks. Young Armyworm larvae feed on all types of grasses, so this next generation of caterpillars may become more of a problem in lawns and pastures.
For more information on Armyworms in crops, you can check out information at the University of Illinois. Purdue University has information on lawn issues with this pest.