Insect Pests of Hardwoods

Hardwood forests carry their own unique threats, including both native and nonnative insects.  Many of these insects have been present in the United States for decades.  Their inherently cyclic emergence cause periods of regional concern and play a vital role in shaping forest structure. They generally attack individual weakened or severely stressed trees. Large infestations develop only occasionally, usually in the aftermath of widespread environmental stress such as drought, storm damage, or wildfire. Overall, their action served to thin forests, reducing competition, leaving the stronger trees, and decreasing the risk of severe outbreaks.

It is important to understand the physiology and history of these hardwood- and conifer-infesting insects to inact proper management when invasions occur.  For example, some hardwood-infesting insects are species specific such as the beech scale and red oak borer. However, both the forest tent caterpillar and gypsy moth defoliate a variety of hardwoods. Knowledge of these and other differences are both interesting and imperative in understanding severity and urgency when dealing with insect infestations.

In this section, more detail is provided about the gypsy moth, Asian longhorned beetle, beech scale insect and the forest tent caterpillar.  Information is also provided for various hardwood borers, such as the red oak and emerald ash borers.