Summary: Of the 43 species of termites found in the USA, 30 have been mentioned as pests, while five of them are considered a serious threat to wood structures and products derived from it. These pests are classified into three general groups, according to their customs: subterranean termites such as Reticulitermitas hesperus Banks, R. flavipes (Kollar), and Coptotermes formosanus Shiraki; dry wood or compact sawdust termites such as Cryptotermes brevis (Walker), Incisitermes minor (Hagen), I. synderi (Light), and Marginitermes hubbardy (Banks); and moist wood termites such as Zootermopsis angusticollis (Hagen).
Soil treatment is typically used for the control of subterranean termites. Local treatment and fumigations are used for the treatment of infestations by moist wood termites or compact sawdust.
The economic expense associated with the actual damage caused by termites and their control in the USA. it was estimated between 100 and 3.4 billion dollars per year according to three reports (Lund 1967, Ebeling 1968 and Anonymous 1974). Based on prevention, control and repair costs Williams and Smythe (1978) estimated that consumers had spent $ 169 million in 11 Southeast States in 1976
This figure was later adopted by the US Environmental Protection Agency (EPA). to arrive at a cost (which included the entire nation) of $ 471 million in the same year (Anonymous 1981a). Maudlin (1982) suggested a figure of $ 735 million, which was also provided by EPA and is probably the most reliable estimate to express the national economic impact of termites in 1981. A study conducted by the Southeast sector of the Society Entomological Insect Detection of the Americas Committee of Prediction and Evaluation in 1983, indicated that a total of 579 million dollars were spent on termite control in 9 southeastern states in 1983 (Hamer 1985).
Comparing this figure with the one provided by Williams and Smythe (1978), one realizes that the costs for the control of termites in the Southeast of the USA. It has tripled in seven years. The data provided by Hamer in 1985 also indicate that termites in the Southeast have a capital impact between 2 and 10 times higher than any other insect pest of any product of agricultural interest. More recently, Edwards and Mill (1986), who extrapolated the data supplied by Pinto in 1981, reached the figure of $ 1.02 trillion for the total of the USA. in 1986. Five distribution zones for the 43 termite species known in the USA. (Adapted from Weesner 1965).
A review of three classic publications (Kofoid 1934, Snyder 1954, Weesner 1965) and a recent publication by Edwards and Mill (1986) revealed that 30 species have been registered as destroyers of wood products or living plants by at least one species. of the authors (as indicated by G or E in Table 2). Species such as Reticulitermes arenincola Goellner, Amitermes coachellae Light, or Tenuirostritermes cinereus (Buckely) can occasionally attack buildings or human products, however their true economic importance is of dubious significance. Of the 43 termites in the US, 5 species Cryptotermes formosanus Shiraki, R.flavipes (Kollar), and R. hesperus Banks are registered as serious pests by all authors. (Snyder did not include C. formosanys on his list because he was not found in the continental US at the time of his writing). The widest distribution of these 5 species contributes to their greatest impact. Four other species: I. snyderi (Ligth), Marginitermes hubbardi (Banks), Hemerotermes aureus (Snyder) and R. tibialis (Banks) are also listed as serious pests by most authors. They are considered less important than the other 5 species, cited above due in part to their relatively limited distribution and lack of accurate field data.
Damage and Control of Termites in Southeast of the US
American termites are classified, roughly, into three groups according to their living habitat.
- The termites of humid wood, generally live in woods with a high degree of humidity, often rotten by the mushrooms.
- Dry wood termites are found in wood with a certain moisture content (10 (70 ca).) While the termites of these two groups form small colonies confined exclusively to wood,
- Colonies of subterranean termites contain a larger population and forage In the soil, the control strategy varies depending on the target species, although the Formosan subterranean species, C. formosanus, is classified as one of the subterranean species, we will treat this species separately, since it requires additional treatment in the control practice. .