These articles are written to apply to the northeastern corner of Illinois. Problems and timing may not apply outside of this area.
Insect pests can vary from year to year in numbers, but some make annual appearances.
Two early season tree pests that show up every season to some degree are the eastern tent caterpillar and the European pine sawfly. White, tent-like webs of eastern tent caterpillar may appear in crabapple, apple, cherry, and plum trees. This insect can be a serious problem since it may consume most or all of the foliage. Trees being defoliated so early in the season may become stressed. Do not mistake this insect for gypsy moth that do not make webs in trees.