Forest Tent Caterpillar
The forest tent caterpillar, Malacosoma disstria, is another native insect of Maryland. This insect is not a looper but is often found with the fall cankerworm. Occasionally it severely defoliates hardwoods. The forest tent caterpillar feeds on oak, gum, and sugar maple growing in forests, especially along rivers and streams.
While defoliation can be extensive and severe, tree mortality generally does not occur unless the trees are defoliated several years in a row. In 1994, 2,900 acres of oak and gum were defoliated in Worcester, Wicomico and Somerset counties, mostly around the Pocomoke River. In 1995, 16,000 acres in this same area were defoliated. These two outbreaks were Maryland's first significant defoliations by forest tent caterpillars in over ten years.
The forest tent caterpillar should not be confused with the closely related eastern tent caterpillar, Malacosoma americanum. Forest tent caterpillars do not make silk tents or webs like the eastern tent caterpillar. Eastern tent caterpillars feed primarily on cherry and crab apple trees along roads. This pest limits visual quality of roadside and yard trees. However, this is temporary and little physical damage is done.