[Pest Profile] Drywood Termites

Scientific Names: Western Drywood Termite —

Incisitermes minor (Hagen)

Southeastern Drywood Termite —

Incisitermes snyderi (Light)

Order/Family: Isoptera/Kalotermitidae

Description
Drywood termite swarmers are light yellowish brown and their wings have three or more dark veins on the leading edge. They are 3/8- to 5/8-inch long and have red-brown heads and thoraxes. The nymphs are creamy white with a yellow-brown head. The soldiers have large, parallel-sided, red-brown heads with massive mandibles that have an unequal number of teeth. Their bodies are light colored. Fecal pellets are hard, elongate-oval in shape, 1/25-inch long, and have blunt ends and six concave sides.

Biology
Drywood termites are a nonsubterranean species. They do not build mud tubes. Depending on the species, swarming occurs anytime, spring through autumn. Most species swarm at night and are attracted to light.

Habits
Drywood termites are found primarily in the southern United States, including the Southwest. They are occasionally found in northern states when the wood (e.g., furniture) they are infesting is moved into these areas. Drywood termites can establish a colony in totally non-decayed wood and maintain residence as long as the wood lasts. The first signs of infestation are swarmers or the accumulation of fecal pellets below “kick out” holes.

Control
During the inspection, signs of infestation, particularly in attics, should be identified. Occasionally, infested wood can be removed and replaced. If reinfestation is a concern, soffit and ridge vents should be screened in order to prevent reentry of swarmers and exposed wood should be treated with disodium octaborate tetrahydrate. Drywood termites are most effectively controlled using a fumigant. This involves tenting the structure and maintaining the concentration of the fumigant for a predetermined amount of time. Heat treatment is a strategy that requires tenting the structure and achieving and maintaining an interior wood temperature of 120°F for 30 minutes. A number of spot treatments, such as liquid nitrogen (cold), microwaves, electricity and applications of residual insecticides are available. The success of these treatments depends on locating the specific area of infestation.