When this occurs, unfortunately it’s too late to do anything at that point. That’s why each fall, before the damage occurs, homeowners who experience regular cankerworm activity are encouraged to band all of their yard trees to reduce damage in the spring.
The sticky bands work by preventing the wingless adult female moths from making it to the tops of the trees. As they emerge from their pupae in the fall, they crawl up the trunk of a tree to the upper branches where they mate with a male, then lay eggs. However, if you intercept them before they make it to their mating and egg-laying sites, then you will probably see considerably less damage. No female ascent means no eggs to hatch next spring!
It’s easy as pumpkin pie! Wrap or staple duct tape or paper tree wrap around the trunk of your tree and evenly cover the band with Tanglefoot Insect Barrier. Tanglefoot is a non-toxic, sticky substance that captures the flightless moths. It is available online and at local hardware stores. If there are crevices in the bark, put cotton or insulation between the tape and the tree trunk so that moths can’t just crawl underneath. Also, if you have an unusually high population of moths, they may quickly cover the sticky band, so checking it and reapplying Tanglefoot every few weeks may be needed.
There is strength in numbers, so persuade your neighbors to do this, too. If you don’t, and the canopy of your tree touches the canopy of their unbanded trees, the moths can easily crawl right over and infest both trees. If both trees are banded, both are protected. This is one situation where “Keeping up with the Joneses” is a good thing!