Fructans: inclusive of inulins, levans, and related fructofuranosides as subterranean termite feeding attractants in termite baiting systems.
PI(s): Miller, Dini M, Mullins, Donald E
Investigators:
Abstract: Currently, there are no attractants or consumption enhancement compounds available for use in subterranean termite baiting systems. Therefore, it takes weeks and often months for termites to begin feeding at the bait stations in significant numbers. The addition of these fructofuranoside polymers to the termites bait matrix would be a significant enhancement to these termite bait systems. The addition of compounds like inulin would cause termites to feed preferentially on the bait matrix rather than other local food resources, and influence those termite workers to recruit additional termites to the bait stations.
Description:
Subterranean termites are the single most
important structural pest in the
There have been a number of methods used to prevent subterranean termite attack on wood structures. The oldest and most commonly used method has been the application of liquid termiticide to the soil around the structure. However, this method requires that large amounts of dilute pesticide be applied to and beneath the foundation. Many homeowners are not comfortable with the invasive applications methods of liquid treatment or the toxicity of the chemicals being placed in their immediate living environment. Therefore, a more novel approach to termite control was developed in the 1990s to eliminate the unpleasant attributes of liquid termiticide application. This approach involved the installation of a termite baiting systems.
Termite baiting systems are applied by installing plastic stations that contain wood blocks (monitors) into the ground around the structure. Termites tunneling in the soil encounter these stations and begin to consume the wood. Theoretically, the termites then recruit additional termites to the bait station so that large numbers of termite workers begin feeding on the monitors. A pest management professional checks the stations monthly. When he or she finds a station that has been "hit" by termites the wood monitor is replaced with a cellulose bait containing a toxicant. The termites in the station consume the bait and then feed it to their nest mates. In this way the toxicant is spread throughout the termite colony and the colony dies.
In spite of the environmental friendliness and unobtrusiveness of termite bait systems, they have several limitations. Not the least of which is the small presence an individual station has in the outdoor environment. Because there is no way to direct termite foraging into the bait system it may take considerable time for termites to discover the stations. In addition, subterranean termites are known to prefer feeding on particular types of wood and wood in certain conditions of decay. In other words, wood whose chemical composition tastes better than other wood available in the same area. If these better tasting food sources are in the same location where baiting is being attempted, the preferred food sources will have a significant impact on the bait system efficacy.
Ideally, the bait system would contain the most attractive, best tasting food resource in the area. Then we could expect subterranean termites to recruit to the bait stations in large numbers and find the bait so delicious that they would eat it preferentially over other competing food resources. For this to be the case, an important question that needs to be addressed. Is there a chemical, or group of chemicals that can be added to a termite monitor and /or bait that would enhance its attractiveness to foraging termites?
As stated above, the primary food source for subterranean termites is wood and termites play a significant role in the ecosystem because they recycle woody materials. However, woody materials are, because of their chemical composition, difficult to degrade. Wood is composed of cellulose (40-50%) and lignins. Celluloses are high molecular weight, linear polysaccharides made up of D-glucopyranose units linked b-1®4. These polymers are difficult for many organisms to digest. However, two major groups of organisms possess the capability to degrade woody materials. These are free-living fungi, and the symbiotic microorganisms that live in the digestive tract of subterranean termites. Symbiotic microbes require the anaerobic environment provided in termite hindgut to digest and convert wood materials into the byproducts useful to termite metabolism: smaller glycopyranose units which ultimately are degraded to hexoses (glucose).
Our disclosure is based on the hypothesis that plant-derived b -linked hexose polymers, such as the fructans, are feeding attractants for termites. This is because they represent less complex molecules than those found in natural woody materials and might be digested more easily by the termite microbial system. Support for this hypothesis is based on our discovery in choice test experiments that cellulose (paper) diets treated with very low concentrations of inulin are significantly more attractive to termite workers compared to other diet sources tested. Thus, we anticipate that (several/all) relatively lower molecular weight b-linked D-fructofuranosyl fructans: the inulins (3,000-5000 Da) and related larger (up to 12,000 Da) fructofuranosides composed of D-fructofuranosyl units linked b-2 ®1, and levans (16,600-33,200 Da), fructofuranosides composed of D-fructofuranosyl units linked b -2® 6, have the potential to be subterranean termite feeding stimulants in termite baiting systems.
Currently, there are no attractants or consumption enhancement compounds available for use in subterranean termite baiting systems. Therefore, it takes weeks and often months for termites to begin feeding at the bait stations in significant numbers. The addition of these b -fructofuranoside polymers to the termites bait matrix would be a significant enhancement to these termite bait systems. The addition of compounds like inulin would cause termites to feed preferentially on the bait matrix rather than other local food resources, and influence those termite workers to recruit additional termites to the bait stations.
Commodities:
Resources: Dodson Urban Pest Management Laboratory
Disciplines: Urban
Audiences: Agribusiness, Environmental Groups, Extension Agents, Homeowners, Researchers
