Subterranean termites are the most destructive insect pests of wood in the United States. They cause more than $2 billion in damage each year, more property damage than that caused by fire and windstorm combined. Several species of subterranean termites are found in the United States; they live in every state except Alaska.

In nature, subterranean termites are beneficial. They break down many dead trees and other wood materials that would otherwise accumulate. The biomass of this breakdown process is recycled to the soil as humus. Problems occur when termites attack the wooden elements of human structures -- homes, businesses and warehouses. Their presence is not readily noticed because they hide their activity behind wallboards, siding or wood trim.

Subterranean termites require moist environments. To satisfy this need, they usually nest in or near the soil and maintain some connection with the soil through tunnels in wood or through shelter tubes they construct. These shelter tubes are made of soil with bits of wood or even plasterboard (drywall). Much of the damage they cause occurs in foundation and structural support wood. Because of the moisture requirements of subterranean termites, they are often found in wood that has wood rot.

Reproductive winged forms of subterranean termites are dark brown to brownish black, with brownish gray wings. On warm, sunny days following fall or sometimes spring rains, swarms of reproductives may be seen. Soldiers are wingless with white bodies and pale yellow heads. Their long, narrow heads have no eyes. Workers are slightly smaller than reproductives, wingless, and have a shorter head than soldiers; their color is similar to that of soldiers.