Seven species of these native termites occur in North America, including I. minor, the western species which is extremely damaging to structures throughout California and Arizona, and I. snyderi, the southeastern species which may cause extensive damage in states from Texas to the east coast.
Drywood termites are somewhat limited to the drier, warmer climates, and generally occur in a band from California to Virginia, in an arc along only the lower parts of the U.S., with occasional incidents in other areas as transients in infested materials. There is no true worker caste, as the nymphs perform the labor and all eventually grow to either soldiers or alates. Winged adults will not be produced until the colony is at least 4 years old, and mature colonies usually have less than 3000 members. Swarming may be during the evening or at mid-day, varying with location, and often only a dozen or so alates will swarm. Further evidence of infestation is the presence of fecal pellets on surfaces, having been pushed out of the galleries by the workers. Colonies may be over 2 years old before this evidence is seen.
Fecal pellets are key evidence, and they are tiny, egg-shaped, and very hard, with several longitudinal depressions on them. Color of the pellets varies depending on the wood infested. Alates have no fontanelle, but they have a single ocellus next to each compound eye and antennae with less than 22 segments. On the wings there are 3 thickened veins that run parallel to each other near the leading edge, running from the base to the wing tip. The wings are usually a pale color. Soldiers have typical jaws, and they are not symmetrical, as they have uneven numbers of teeth on their inner margin. The antenna is composed of 10 or 11 segments, and in some species the third segment may be longer than the fourth and fifth segments combined, in other species it is shorter. The color is a reddish brown.
Characteristicts Important to Control:
Control is by either fumigation of structures or infested objects, or by injection of a residual insecticide into the galleries in the wood. Consideration must be given to the small colony size, and the possibility that multiple colonies may exist within a single structure. Alternative treatments methods other than fumigants are becoming more widely used.