Economic Effects and Control

Termites are known in temperate climates chiefly by the damage they do to buildings, furniture, books, and certain fabrics. Termites are nevertheless beneficial to man. They increase the soil's productivity by loosening and fertilizing it, making it more water-absorbent, and turning plant material into humus.

In the United States, the greatest amount of damage is caused by subterranean and dry-wood termites. Subterranean termites are found mainly from Massachusetts south to the Gulf states and in coastal California. In the United States, dry-wood termites are found in isolated areas along the southern Atlantic coast, the coast of the Gulf of Mexico, the Mexican border, and the Pacific Coast.

The U.S. Department of Agriculture emphasizes the importance of preventive measures, since it is extremely difficult to get rid of termites once they have infested a wooden structure. Among recommended measures against subterranean termites are chemical treatment of the soil of building sites, use of foundation materials other than wood, and use of chemically treated or naturally termite-repellent wood for woodwork that must come in contact with soil. Chemicals that occur naturally in the heartwood of such trees as California redwoods, longleaf pines, camphor trees, and teaks make these heart-woods to some degree repellent to termites.

Shields of noncorrosive metals such as copper and galvanized iron help prevent infestations by subterranean termites. The shields serve to provide a barrier between hollow masonry foundations and the wooden parts of a building.

To prevent dry-wood termite infestation, construction materials should be termite-resistant, and all openings into the building should be screened. Regular inspection of buildings is recommended.

Services of a professional exterminator are usually necessary when termites have infested a structure. Replacing damaged woodwork and treating undamaged wood with chemicals are effective measures. Fumigation is sometimes used to kill dry-wood termites. Termites in furniture can be killed by heating the furniture in special kilns at a temperature of about 150° F. (66° C.) for a few hours, or by exposing it to a temperature of 30° F. (-1° C.) or less for several days.

Termites make up the order Isoptera. In the United States, the common genera of destructive termites are: subterranean, Reticulitermes; drywood, Kalotermes; damp-wood, Zootermopsis.