The eastern tent caterpillar (ETC) (Malacosoma americanum) is a native pest. Populations fluctuate from year to year and are more problematic when numbers are high.
ETCs are identified by long white hairs, a white stripe along the back and a row of oval blue and black spots on each side. Their bodies display black, blue, brown and yellow coloring. They are most often recognized by the silken tents constructed in the branch unions of trees. Caterpillars leave the tents to feed.
ETC do not typically kill trees and pesticide use is neither necessary nor recommended. Healthy trees usually recover from defoliation (damage) they cause. As a native species, ETCs are part of the food web, serving as prey for birds such as Baltimore orioles, as well as other natural enemies.
If your tree has been stressed for a long time and continues to be defoliated year after year, it can become a serious issue. In that case, you may need to consider control methods and ways to support your tree’s health. When populations are high, monitoring is advised before considering manual control measures (e.g., hand-picking). For large trees, we recommend consulting with a Certified Arborist for specific recommendations.