Forestry, Wildlife & Fisheries News |
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Aggressive intruders...Scientists study termites to find effective controlBy Charmain Tan Courcelle MISSISSIPPI STATE -- Neighborhood watch programs tend to deter criminal activity, and Mississippi State University researchers are hoping increased surveillance will have a similar effect on a devastating species of termites at work in the state. The Formosan subterranean termite is a nonnative species of termite. Experts consider it to be one of the most aggressive and destructive species of termite in the world. It's believed this pest first entered the southeastern United States on crated military supplies returning from the Pacific theater after World War II. These termites may be spreading beyond the southeastern states, California and Hawaii and moving further through the country. Mississippi Agricultural and Forestry Experiment Station and other MSU scientists are working to determine the extent and severity of Formosan subterranean termite infestation in Mississippi. They are looking at changes to the population over time and assessing methods of termite management and control. These studies may uncover a chink in the termite's armor that could be used in the development of methods to control this pest. Christine Coker, MAFES environmental scientist, is part of a team at the Coastal Research and Extension Center in Biloxi that is assessing an area-wide management strategy. MAFES is working in partnership with Operation Full Stop, the national campaign against Formosan subterranean termites led by the U.S. Department of Agriculture's Agricultural Research Service. Unlike native subterranean termites, Formosan subterranean termites do not have to return to underground nests after foraging. If sufficient moisture is available, for example from leaking pipes, this species can build nests above ground in walls or live trees. Formosan subterranean termites are not restricted to dead trees and processed wood for food -- any material containing wood fiber, or cellulose, is a potential food source for this species. Because of the large size of Formosan subterranean termite colonies, this pest consumes more wood than its native cousin. To prevent further destruction and infestation by Formosan subterranean termites, project scientists have designed and are assessing an area-wide termite control approach. This strategy protects all structures within a given area or neighborhood by eliminating or reducing the size of the termite colony. Conventional barrier treatment methods only protect individual structures and don't reduce or eliminate a colony. Formosan subterranean termites are social insects that forage over wide areas and develop more extensive colonies than native species. Because of this behavior, scientists say treating single buildings is not an effective method of Formosan subterranean termite control. "With an area-wide approach to termite control, the entire colony is affected, not just individual termites. So, this approach should eliminate or at least reduce the threat of further infestation," Coker said. Monitoring studies have confirmed the presence of Formosan subterranean termites in Mississippi and continue each spring to track their occurrence and spread in the state. As a result of this work, researchers have confirmed the spread of Formosan subterranean termites into forested areas. This is the first time they have been documented to spread from urban areas into naturally forested areas. These colonies provide a "field lab" to study the behavior of Formosan subterranean termites in natural environments, away from man-made structures. Scientists involved in the project hope their studies in the "field lab" and with the area-wide management systems will lead to effective baiting techniques and methods to detect termite activity and to eliminate Formosan subterranean termite populations. Because the Formosan subterranean termite is not native to the United States, it has no natural predator in this country. MSU forest products scientist Susan Diehl is working with USDA scientists to identify organisms from the termite's original home that might be used as biological control agents. In its native land, enemies like the fungi Metarhizium anisopliae and Beauveria bassiana keep the Formosan subterranean termite in check. Diehl is screening fungi isolated from soil and termite samples collected in China by her ARS collaborators for these and other natural foes. Diehl said the task of identifying helpful fungal species rapidly is made difficult because there is limited information about fungi that can cause disease in termites and other insects. "We hope to improve the current fungal pathogen databases, which should increase our ability to pull out fungi that seem promising as termite biocontrol agents," Diehl said. The screening process is the first step in a long battery of tests that any potential biocontrol agent needs to pass before it can be adopted for use. Once Diehl's team has provided ARS scientists with a list of potential agents and their identifying characteristics, they will need to determine if these are safe for use in the United States -- nonthreatening to humans, animals, native plants and beneficial insects. "After these extensive tests, the final challenge will be whether we can introduce a termite pathogen that can survive conditions in New Orleans or anywhere else that it's introduced, that can be incorporated as part of a bait system and that will be effective in killing Formosan subterranean termites," Diehl concluded. Released:
Feb. 17, 2003 |
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