What's the Problem?
The caterpillars feed principally on the leaves of poplar and willow trees and less commonly on oak. In new outbreaks, satin moth is often seen to prefer hybrid poplar species such as the Northwest, Griffin, Silver and columnar types which are planted here as landscape ornamentals. Successive heavy attacks over 3 years will likely result in the dieback of branches, or even whole trees.
What Can I Do?
A small parasitic wasp (Cotesia melanoscela) attacks and for the most part now suppresses satin moth populations in the area. Typically spraying is no longer required.
There are a couple of cultural practices a homeowner can use to help control satin moth on a tree. The greenish egg masses concentrated on the lower areas of the tree can be easily scraped off in July with a dull blade and destroyed before they hatch.
A sticky band can be used to intercept much of the upward movement of young caterpillars that overwinter in bark crevices on the lower trunk area. Such a sticky band trap should be established by the end of April and monitored throughout the month of May to ensure the sticky surfaces do not become saturated with emerging caterpillars.