These plants may be partly or almost completely defoliated. Defoliation can be detrimental to tree heatlh and survival, especially in evergreens where needles are not replaced. Management Management of bagworm should occur before extensive feeding damage takes place. Mechanical management through the removal and destruction of overwintering bags is effective and environmentally friendly. Chemical control should be initiated while the caterpillars are small, soon after all eggs have hatched.
Some insecticides are more effective on young caterpillars.
Chemical treatments applied in late summer after the caterpillars stop feeding or during the winter are not effective. For more information on managing bagworms with chemical and biological controls, see the University of Illinois Urban Pest Management Handbook or contact your unit office of the University of Illinois Cooperative State Research, Education, and Extension Service. Prepared by John E. Lloyd , Extension Entomologist, University of Illinois and Illinois Natural History Survey. For additional copies, contact your unit office of the University of Illinois Cooperative State Research, Education, and Extension Service. Urbana, Illinois 1995.