Institute for Transportation

Insects causing damage to wood products or building components comprise two groups: (1) those that infest non-seasoned wood (eg, logs, freshly-cut materials), or (2) those that can infest (or re-infest) seasoned wood. Many species of insects can infest wood before it has been dried, but relatively few species can infest or re-infest wood that has been dried to below approximately 20% moisture content. Since most building components used in the United States are both heated and dried in kilns or presses to well below approximately 20% moisture content, insects that have infested the wood prior to seasoning are killed and no additional damage will occur. However, wood salvaged from structures (eg, barn wood) and re-used often contains insects and, unless fumigated or kilndried prior to re-use, the insects can continue to infest wood in the new structure. Insects capable of infesting and feeding on seasoned wood include beetles such as anobiids, lyctids, old-house borers, and bostrichids as well as subterranean, dampwood and dry-wood termites. Insects that excavate nest sites in seasoned wood but do not consume wood as a food source include carpenter bees and carpenter ants. An understanding of the basic biology of the insects and the types of wood that they infest will enable one to identify the insect causing the damage and to formulate a management program.