Subterranean termites are the most destructive insect pests of wood in the United States. They cause more than $2 billion in damages each year—more property damage than that caused by fire and wind storms combined.
Dead trees and brush are the original food source of subterranean termites. When land is cleared of this material and houses are built on these sites, termites attack the structures. Termites can enter buildings through wood in direct contact with the soil, by building shelter tubes over or through foundations, or by entering directly through cracks or joints in and under foundations.
Because subterranean termites forage in soil, it is important to keep structural lumber from direct contact with soil. Keeping the lower foundation walls and siding clear of vegetation or mulch makes it easier to inspect for termite shelter tubes.
Subterranean termites need moisture for survival. Leaky plumbing, air conditioning condensate, and any portion of a building and its perimeter that collects excessive amounts of moisture should be corrected to maintain an environment less attractive to subterranean termites. Wood pressure-treated with preservatives such as chromated copper arsenate (CCA) is resistant to termites, and use of treated wood can minimize available food sources for subterranean termites.