Reduce the number of spongy moth (Lymantria dispar) [formerly known as “gypsy moth”] caterpillars in your trees by putting up barrier bands before the caterpillars start to hatch in mid-May. Caterpillars crawling up the trees will mire down in the sticky material and die. Bands can keep caterpillars from migrating to other trees or from climbing back up if they fall off the tree (surprisingly common!).
Make barrier bands using duct tape and a waterproof, sticky material such as the Tanglefoot or petroleum jelly. When the bark is dry, wrap duct tape around the tree, shiny side out, pressing the tape firmly into the bark cracks to prevent caterpillars from slipping under the bands. The tape should be wrapped a few inches wide and placed around the tree trunk at chest height – about four feet above the ground.
Try using sticky barriers like duct tape and petroleum jelly to trap caterpillars from April into the summer.
A band of duct tape is needed to protect the tree bark from the sticky material, which could disfigure or kill the tree if applied directly. Smear the sticky material along the center of the band. (If you choose to use petroleum jelly, allow at least two inches of uncoated band under the jelly as it can melt and flow downward.) Periodically check the barrier bands to make sure they have not been clogged with insects, dirt or debris. Apply more sticky material as needed; check especially after a rain. You can take the barrier bands down in late July after spongy moth caterpillars have pupated.
Recently, similar sticky-band trapping methods (for the invasive spotted lanternfly) have caused concerns for birds in Pennsylvania and other mid-Atlantic states. To help reduce risks to birds, consider placing chickenwire or mesh screening over the sticky bands to prevent birds from contacting the sticky surface. See this page for additional info about preventing bird contact.