Bagworms affect many species of evergreens and several deciduous trees, constructing baglike shelters from which they feed on foliage. Because of the immobility of the females, once established on a tree, bagworms are there to stay, according to the Penn State University Extension, unless you take steps to control them.
Several insecticides are labeled for bagworm control, according to the University of Missouri Extension. These include acephate, bifenthrin, Bt, carbaryl, chlorpyrifos, diazinon, lambda-cyhalothrin and malathion.
Insecticide approvals change over time. Always read the instructions on the label carefully to confirm that the product is not only approved for controlling bagworms but also safe for the plant to which you intend to apply it.
Bagworms construct a bag around themselves made of plant debris, presenting a challenge to control efforts. Because of this, if you are using an insecticide against bagworms, the Penn State University Extension recommends applying it early, while the larvae are small and most susceptible. Contact your local extension office to learn the best season for chemical bagworm control in your area.
First published in 2000, Dawn Walls-Thumma has served as an editor for "Bartleby" and "Antithesis Common" literary magazines. Walls-Thumma writes about education, gardening and sustainable living. She holds a Bachelor of Arts in psychology and writing from University of Maryland and is a graduate student in humanities at American Public University.