|Urban Knowledge Master|
|Cryptotermes brevis (Walker), West
Indian drywood termite
Incisitermes immigrans (Snyder), Lowland tree drywood termite
Neotermes connexus (Snyder), Forest tree drywood termite
Julian R. Yates III
Extension Urban Entomologist
College of Tropical Agriculture and Human Resources
University of Hawaii at Manoa
The lowland tree termite is found at low elevations in dead branches of koa haole, panex, banyan trees, etc. The forest tree termite lives at higher elevations and is often found in dead koa branches and trunks. The West Indian termite was probably introduced from tropical America before 1869; it has spread to all of the major islands. It is a very serious pest in the Caribbean, especially Puerto Rico. It is also present in Florida, South Africa, and China, and the Marquesas Islands.
The lowland tree termite rarely attacks homes. The lowland and forest tree species are considered beneficial because they attack dead plant limbs and help recycle nutrients to the environment for other organisms. The West Indian termite feeds on most types of wood found in and outside the home, but it prefers hardwoods, which are often used to build fine furniture. It also attacks books and other materials containing cellulose.
A typical one-year-old West Indian termite colony contains 10-15 individuals. Soldiers are not produced during this period. In well established colonies the number of individuals rarely exceeds 200; in heavily infested wood, however, colonies may unite, resulting in higher total numbers.
During the first month after pairing and mating, the female lays two eggs, and approximately four eggs each during the second and third months. The eggs are pink and are shaped like jelly beans. At 27ūC the eggs hatch in approximately 56 days.
Newly formed nymphs are fed predigested food by the adults or older nymphs because the new nymphs do not have the required symbiotic protozoa for cellulose digestion. All nymphs perform the duties of true workers and eventually become reproductive adults.
After a suitable site to start a colony is found, the male and female tunnel along the grain of the wood, establish a nest and the female lays a few eggs.
The use of heat as the killing agent in a recent development in drywood control. Infested structures to be treated are tented/sealed and the temperature is rapidly raised to 66ūC to bring the interiors of the structure to 49ūC. This is maintained for 30 minutes. This procedure may be used to control drywoods in furniture, picture frames, etc.
Two control strategies can be applied to the West Indian drywood termite: prevention and remedial control.
Preventative methods deter attack by this pest and include pressure treated wood with the active ingredient, chromated copper arsenate (CCA), or Osmose and Wolman pressure treated wood. Although the use of this pesticide may be insufficient to prevent attack by the Formosan subterranean termite from established colonies, it may be efficacious against Formosan and West Indian adult termites seeking a place to start a colony. CCA treated wood cannot withstand a sustained attack by Formosan termites because of the insufficient penetration of the ingredient into heart wood of Douglas fir, the principle structural wood used in Hawaii. Recent tests conducted by the termite research laboratory, University of Hawaii, Manoa, revealed a second formulation which proved to be highly effective against the Formosan termite. The material is ammoniated copper zinc arsenate (ACZA). Wood pressure treated with this formulation were untouched, and killed the Formosan termite. The penetration of ACZA into Douglas Fir was superior. Although tests did not include the West Indian termite, one can confidently assume that ACZA would be effective in stopping this less aggressive pest. ACZA pressure treated wood is available in Hawaii.
The use of non-preferred wood is the second preventative method. Tests have indicated that softwoods are less preferred than hardwoods by the West Indian termite . However, their preference for Douglas Fir was not established.
The procedure is initiated by locating the colony within the infested wood. This can be accomplished by tapping wooden members with the handle of a screw driver or similar devise to detect hollow areas. Additionally, one can look for "kick-out" holes which are about the size of a pin head and which may be opened or sealed. These holes are more easily found by focusing on areas associated with fecal pellets that have been kicked out of galleries.
When the galleries are located, inject an insecticide within. An aerosol formulation is preferred for complete coverage, as opposed to a liquid or dust formulation. A convenient and safe aerosol to use is "Term-Out". It is provided with a hose and needle-nozzle for ease of application, and the active ingredient, resmethrin, has a low mammalian toxicity, and is odorless.
A second possible remedial control method is the application of high electrical voltage to termite galleries. Such a device, known as the electrogun, has been used for some time in California and certain parts of Canada, and has only recently been introduced to Hawaii. Until controlled scientific experimental tests are conducted under Hawaii's conditions (temperature, humidity, wood type, termite species, etc.), however, the true effectiveness of this method cannot be known.
The third, and perhaps mostly widely used control method is fumigation. This method, however, should be employed only after a thorough inspection is made of the entire structure to assess whether fumigation is warranted. Compared to spot treatment, it is a relatively expensive method and should be reserved only for controlling widespread infestations within a dwelling. Infestations that are limited to one or two spots can be spot treated as described above, or if the infestation is in a furniture piece, for example, vault fumigation is in order. The fumigant, VikaneR (sulfuryl fluoride), when correctly applied, is very effective against a number of pests. It is important to remember, however, that fumigation is a remedial control method and not a preventative method to control household pests. Repeated fumigations to control the West Indian termite in Hawaii on a regular schedule (for example, every three years) is unnecessary. Regularly scheduled inspections are of prime importance to prevent widespread infestations of this pest, and costly fumigations.
Smith, Eric H. and Richard C. Whitman. 1992. NPCA Field Guide to Structural Pests. NPCA.
Tamashiro, M. Biology and control of the West Indian drywood termite, Cryptotermes brevis in Hawaii with notes on fumigation. Hawaii Pest Control Association lecture handout. Unpublished.