What's the Safest Way to Get Rid of Subterranean Termites?

A Reader Writes The Green Guide:

We are currently facing issues with subterranean termites. We have three small children and many pets that we do not want to expose to chemicals. How do we best treat subterranean termites without harming our children? We have heard great things about Sentricon and Exterra, but are they really safe? We have also heard about a chemical application used in Hawaii that is "supposed to be" safer than salt?

Any recommendations would be appreciated. Thanks in advance for your assistance.

Best Regards,
De De Curry
Northern California

The Green Guide Responds:

Subterranean termites are one of the two major house-attacker termites in the U.S. They move great distances and can infest neighboring homes with their huge underground colonies, which may contain up to a quarter of a million insects at one time. They also build distinctive tubes, which allow them travel above ground, across foundations, and between the soil and the wood. Because they need constant moisture from the soil, their nests are vulnerable to exposure: simply opening up a nest to the air will kill the inhabitants. However, with nests often deeply underground, or under foundation, this is not always manageable.

One fumigation treatment for termites, Vikane, is an extremely toxic nerve poison, and can be absorbed by furniture and held for up to 40 days after fumigation. Moreover, this type of fumigation (which involves tenting the entire house) only kills termites above ground, and does not attack the nests below ground, leaving the house likely to experience a resurgence later. Obviously, this type of fumigation is something to avoid. There are also many chemical treatments that involve injecting walls or soil with inorganic pesticide chemicals that can get into ground water. Unfortunately, until 1986, the most common chemical injected into soil was chlordane, a known carcinogen, which has now been banned.

There are quite a few safer, biological methods that can be equally effective in controlling subterranean termite infestations. Sentricon, which is a termite control system using Recruit, a fatal insect growth regulator, uses bait stations. Once consumed by the termite, the regulator spreads through the colony, killing them off slowly. Exterra, a similar baiting system, has the advantage of bait stations that can be refilled without disturbing the feeding termites, which streamlines the process somewhat. Neither of these methods work as rapidly as fumigation methods, or chemical injection, and may take months to completely wipe out a colony. However, they do attack the problem at the colony, which means that once they work, there is less chance for resurgence. These methods are environmentally safer, and safe for adults, kids and pets since their pesticides are specific biological control methods for termites. However, it is important to work with a seasoned pest control operator, since bait stations must be placed in close proximity to the colony.

Once you find a pest control specialist who uses biological and environmental methods, discuss the range of options. In some case, operators can inject colonies with a fungus called Bioblast, which infects the termites with a parasitic organism, not harmful to humans. Some operators use methods that inject growth hormones into cracks in the foundation as well. In Hawaii, much research has gone into designing physical barriers, especially using sand, which prevent termites for reaching the house, and these kind of barrier methods may be a good way to prevent a resurgence of termites in a previously infected home. Once you find an operator you can trust to provide non-toxic, environmentally sound options, it will be easier to establish the safest and most effective methods for your specific problem.

Biological control methods also benefit from attention and upkeep by the home owner. If you suspect a colony, use a shovel to loosen the soil and expose the colony to air, allowing other natural predators, such as ants, to enter as well. Break up any travel tubes that you might see near foundations, diverting the paths of subterranean termites and slowing their destruction process. Consider physical barriers for the parameters of your house to help protect against resurgence.

RESOURCES:

Tiny Game Hunting by Hilary Klein and Adrian Wenner (University of California Press, Berkeley; 2001).

Sentricon System Information, www.dowagro.com/sentricon

Exterra System Information, www.termite.com/exterra.html