Species

Termites belong to the order Isoptera.

Species commonly found in the Northwest:

• Nevada Dampwood - Zootermopsis nevadensis
• Pacific Dampwood - Zootermopsis angusticollis
• Western Subterranean - Reticulitermes hesperus
• Arid-land Subterranean - Reticulitermes tibialis

Host/Site

Dampwood termites are found along coastlines and in cool, moist areas. Colonies live in fallen wood or beneath the ground. If wood is extremely moist, dampwood termites do not have to be underground. They can thrive in wood paneling wet from water leaks, etc.

Subterranean termites pose the greatest threat to wooden structures. These termites begin from the soil then create tunnels through wood or move within self-constructed shelter tubes composed of soil and wood pieces.

Identification

Appearance Subterranean termites can range in color from white, to dark brown, to brownish black, to light brown and translucent. There are four castes: reproductive kings and queens with long wings and dark bodies; short-wing males and females; soldiers; and workers. The soldiers are wingless, have white bodies, and pale yellow heads without noticeable eyes. The workers are wingless, similarly colored to soldiers, and are smaller than both soldiers and reproductives. Dampwood termites are larger than subterranean termites (1/3 inch), and share similar physical characteristics. They don't have a worker caste system and swarms tend to be smaller in number.

Subterranean Termites Photo courtesy of Agricultural Research Service of the U.S. Department of Agriculture

Life Cycle

Termites experience incomplete metamorphoses. They develop from egg, to nymph, to adults.

Kings and queens of colonies can live for decades. They swarm usually in late summer and early fall, but can also swarm in the spring. Swarming is often the first indication of an infestation. Workers and soldiers can live up to several years.

Natural Enemies

Among others, common ants are known to eat termite colonies. They are not, however, recognized as biological controls for infested houses.

Monitoring

Regularly inspect wood beams, joists, sills, as well as the foundation. Look for markings (tunneling, darkened spots or blisters, fecal pellets) and strike the wood with a screwdriver to test its strength.

Action Threshold

Termites, if allowed to multiply and development populations indoors can have devastating effects on homes and other structures. Act immediately, when an infestation is discovered, large or small.

Physical/Mechanical Controls

Preventative measures to keep termites away from the home include:

• Underneath the building, keep structural wood at least twelve inches above exposed soil.
• Maintain good ventilation around the foundation and within attics.
• Place screens over vents to prevent winged termites from entering.
• Remove or seal any wood within contact of soil.
• Destroy shelter tubes to block subterranean termite paths to wood.
• Use sand barriers around the foundation.
  *Use size 16 mesh sand and place it around the foundation and crawl spaces. The sand makes tunneling impossible for subterranean termites and provides a barrier from exposed wood. The sand should be 18 inches wide and 3 inches deep along the foundation.
• If a foundation has yet to be poured, place sand before pouring concrete.
  *For dampwood termites, if the colony is small, removing the infested wood and maintaining low levels of moisture can destroy the nest.
  
  

Biological Controls

Currently, there are no conclusive reports of biological controls for termites.

Chemical Controls

Termite colonies build slowly and controls can be taken up to six months after initial sighting. Unfortunately, there are not sufficient products for toxic-free alternatives for termite control. Chemical treatment is not recommended initially for dampwood termites. They can only live within moist environments; thus, sealing sources of moisture within a home can be sufficient. Subterranean and dampwood termites cannot be eliminated by fumigation, heat treatment, freezing, or electrocution devices because the nests are usually underground—these above treatments do not reach the colony.

With few exceptions, professional pest companies are used for termite removal from buildings and homes. Professional companies tend to be best for handling and targeting zones. Improper application of insecticides can contaminate heating ducts, radiant heat pipes, plumbing pipes, and could potentially contaminate groundwater

Consult with trusted companies to decide what might be the least toxic way to rid the termites. Insecticides or baits must be complimented with destroying and sealing points of access and/or nests. Chemicals such as imidacloprid and fipronil are less toxic and available for use. Hire a termite control company to conduct an inspection of the house or building prior to using chemical treatments.

Be sure to get at least three different estimates before committing to a company's treatment. Most importantly, take the time to consider which treatment is most appropriate given the extent of the damage. The most common means of controlling subterranean termites is to apply insecticides or baiting programs.

Baits can be used for subterranean termites. It requires no drilling, trenching, or applications of insecticides to soil or the structure. Most baits are handled by professional pest control companies.

Common ways to spot treat wood is through pressure treatment. Borates, though toxic, are low in human toxicity. If used on exterior wood they must be sealed.

If treating wood on the exterior of the home or building, use "exterior grade." If not handled properly, chemicals in the lumber can leach from the wood and into soil.

Ultimately, consult with professionals, and take the time to consider the least harmful and most effective treatment system available.

References

Cox, Caroline. "Protececting Your Home From Subterranean Termite Damage." Northwest Coalition for Alternatives to Pestacides. 2004. 13 Nov. 2008. <http://www.pesticide.org/subterraneantermites.html>

Gold, Roger E., Michael E. Merchant, Grady J. Glenn. "How to Select a Termite Control Service." Texas Agricultural Extension Service. The Texas A&M University System. 13 Nov. 2008.
<http://insects.tamu.edu/extension/bulletins/l- 1785.html>

Jones, Susan C. "Termite Control." Ohio State University Extension Fact Sheet. The Ohio State University. 13 Nov. 2008. <http://ohioline.osu.edu/hyg-fact/2000/2092.html>

Merchant, Michael E., Richard Gold. "Commonly Asked Questions About Subterranean Termite Control." Insects in the City. Texas A&M AgriLIFE Extension. 2003. <http://citybugs.tamu.edu/FastSheets/Ent-1006.html>

Miller, Dini M. "Subterranean Termite Biology and Behavior." Virginia Cooperative Extension. Virginia Tech and Virginia State University. 2002. 13 Nov. 2008. <http://www.ext.vt.edu/pubs/entomology/444-502/444-502.html>

"Subterranean Termite Signs of Infestation." Virginia Cooperative Extension. Virginia Tech and Virginia State University. 2002. 13 Nov. 2008. <http://www.ext.vt.edu/pubs/entomology/444-501/444-501.html>

"Termites." How to Manage Pests. 2001. University of California IPM online. 13 Nov. 2008.
<http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7415.html>