Big appetites
Spongy moth caterpillars have a huge appetite. They eat the leaves or tender growing parts of over 300 types of trees and shrubs. They can strip entire forests of their vegetation in areas where they become established.
While a deciduous forest (trees that lose their leaves in the winter) can re-leaf out and recover, multiple years of infestation can kill the trees. But when the caterpillars eat the needles from evergreen trees, those trees can die in just one year of infestation.
Habitat Destruction
Eating all the foliage and killing trees has a significant impact on not only the trees but the other wildlife that depend on them. From reduced food and shelter for native species to warmer streams for fish, spongy moth infestations can dramatically impact a wide range of native butterflies and moths, mammals, birds, fish, and more.
Human Impacts
Humans also feel the negative effects of the spongy moth. Reduced shade and damaged trees can make it difficult or impossible to enjoy parks, forests, and even backyards. During caterpillar feeding, frass (poop) rains down from the trees, covering picnic tables, making sidewalks slippery, and surprising the unwary person drinking their morning coffee. In high numbers, caterpillars and droppings on the roads have even been known to cause car accidents. Finally, some people are allergic to caterpillar hairs and can get rashes from being in contact with them.
Population Explosions
Where there are a few spongy moths, there are sure to be a lot of spongy moths very quickly. Females can lay up to 1,000 eggs in the summer. If not dealt with quickly when a population begins to establish, it can quickly grow beyond levels that can be controlled. That is why WSDA monitors the state closely and proposes eradication whenever a population appears to be trying to establish.
