Caterpillars of the Cankerworm, Winter Moth and Gypsy Moth have been actively feeding on deciduous hosts since May 8. The first two of these defoliators can be identified by their light green larvae; the latter by its black larvae. Damage symptoms caused by the young larvae range from small, irregular holes in the leaves to the skeletonizing of the leaves. Later, as they increase in size, they consume all but the mid-rib of the leaves. Use Bacillus thuringiensis (Bt) to manage light infestations. If the infestations are heavy, treat with a registered pesticide until the end of May.