PJ Liesch, an entomologist with the Division of Extension at the University of Wisconsin-Madison, said defoliation could slow the growth of trees that may be logged for lumber. From a forest health perspective, it could also leave them vulnerable to secondary pests like the two lined chestnut borer. The insect, a native relative of the invasive emerald ash borer, typically targets weaker oak trees and starts killing branches in the upper canopy.
With spongy moth increasing for several years now, Liesch said there’s a lot of stressed oak trees. “So the secondary insects and problems can start popping up, and then it’s a very slippery slope leading to tree death in some situations,” Liesch said.