Biology of the Leaf Crumpler, Acrobasis indigenella, in Central Illinois1

Acrobasis indigenella (Zeller) is a pest of many species of Rosaceae. The insect has a univoltine cycle, overwintering as immature larvae from eggs deposited in July and early August. Adult emergence reaches a peak in mid-July. The larvae consume the foliage of the host plant and using bits of leaves and fecal pellets, construct silken cases on the branches, giving the plant an unsightly appearance. The average duration of the egg, larval, pupal, and adult stages is 10 days, 11 months, 12 days, and 10 days, respectively. Nemorilla pyste (Walker) is an internal dipterous parasite of the leaf crumpler larva.