Effective Termite Eradication

One of the most effective ways of getting rid of a termite colony is with a toxic bait matrix—a combination of materials that the pests like to eat and a slow-acting toxic agent that ultimately kills them. SRRC entomologists Juan Morales-Ramos and Guadalupe Rojas are experts on termite nutritional preferences, and they have created several matrix formulations.

Rojas says, "In the lab, we have hundreds of petri dishes filled with termites, and we use the termites like sensory panelists. We feed them different nutrient mixtures to find out what they like to eat best."

In October 2002, Rojas and Morales-Ramos completed a 2-year, areawide, bait matrix study in residential Mississippi neighborhoods in Poplarville, Picayune, and Biloxi, at Keesler Air Force Base. The research was done with entomologist David Nimocks, president of Ensystex of Fayetteville, North Carolina. The scientists have a cooperative research and development agreement with Ensystex, and ARS has granted an exclusive license to the company to manufacture the bait matrix. Other collaborators included scientists from Mississippi State University's Coastal Research and Extension Center, including David Veal, head of the center; researchers Christine Coker and Patricia Knight; and research associates Margaret Lockwood and Larry Etheridge.

Mississippi has a growing Formosan termite problem, although populations there aren't nearly as dense as they are in New Orleans. Using an ARS bait matrix containing chlorfluazuron, ARS and Ensystex researchers were able to reduce native and Formosan termite activity by 95 percent in one test area in Picayune. In a related study, they found that one of their bait matrices, which incorporates diflubenzuron, was also effective against red imported fire ants. These pests must be controlled in and around bait sites because their presence repels the termites. And fire ants are another major urban pest. Having filed a patent application on the ant bait matrix, the scientists are currently working with Ligia Hernandez, product development manager for Waterbury Co., Inc., Independence, Louisiana, which has applied for a license for its manufacture.

Rojas says that they have started new experiments in cooperation with MSU, Ensystex, Waterbury, and James M. Spiers and Formosan termite personnel at ARS' Small Fruits Research Unit in Poplarville. The goal is to focus even more attention on integrated methods to best control both termites and ants.

Termites vs. Essential Oils and Mold

By studying different plant extracts, entomologist Gregg Henderson at the LSU AgCenter has found compounds that are effective against termites and other insects, including red fire ants, mosquitoes, ticks, and cockroaches. One such compound, nootkatone, is derived from essential oils in vetiver grass. Recently, Henderson and his collaborators have been evaluating how well compounds such as nootkatone work to protect wood from Formosan termites. Results have been promising. Henderson says the compounds seem to affect termites' neurotransmitters and stop their movements. If further experiments prove successful, these essential oils could replace chemicals such as copper, chromium, and arsenic currently used to treat lumber against insect attack.

At ARS' Natural Products Research Unit in Oxford, Mississippi, chemists are extracting natural compounds from other sources, seeking new active ingredients that could act as termiticides or form the structural basis for developing such ingredients.

SRRC microbiologist Maureen Wright has been having good success with a natural termite control agent. It's derived from a cottony mold called Paecilomyces fumosoroseus. Wright heard about its biological control abilities from Mark Jackson, a microbiologist with ARS' National Center for Agricultural Utilization Research, in Peoria, Illinois.

Jackson had developed an efficient and relatively inexpensive way to produce large amounts of the fungus to control whiteflies, aphids, and other agricultural pests. Wright tested samples of the mold against Formosan termites and came away with impressive results: It killed 100 percent of the termites in less than a week.

Wright has demonstrated that termites exposed to the mold transfer it to other members of their colony. She's also shown that it can be effective in various settings. Retired SRRC chemist Bill Connick helped develop several application formulations. A termite-infested tree, for instance, might require a different application method than a wooden structure. ARS is currently negotiating with a company that wishes to license the technology.