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Termite Research
THE MISSION
of the Wood Products Insect Research Unit (SRS-4552) is to improve the
protection of wood products against subterranean termite damage, define the role
of termites in forest ecosystems, and understand their impact on forest health.
To accomplish this mission, research is organized into four problem
areas: (1) develop, refine, and assess new, improved, and alternative compounds,
materials, and treatment techniques for effective protection against damage
caused by termites; (2) investigate the biology, ecology, and behavior of
termites in forest ecosystems to promote the development and efficacy of
protection techniques; (3) investigate the role of termites in nutrient cycling
to promote an understanding of forest, soil, and watershed health and
productivity; and (4) investigate factors that allow the Formosan termite to
survive standard termiticide treatments. Research is formulated with an understanding that termites play dual roles as pests in urban environments and, conversely, as contributors to forest health and productivity. Their role in forest ecosystems as wood decomposers contributes to nutrient cycling, soil fertility and stability, forest productivity, and water quality -- aspects that are little studied and poorly understood. Their role as wood-product pests is better understood, yet increasing restrictions on insecticides make their control less certain and more costly. These divergent issues are important in light of the increasing demands placed on the decreasing forest acreage worldwide. As providers of forest-related research, it is critical that the U.S. Forest Service address the challenges placed on forest resources and associated industries. These challenges include regulation of forest health, timber production, and preservation of wood products to lessen the demands on existing forests and reduce the costs to American homeowners and businesses. Problem Area 1: Develop, Refine and Assess Treatment Techniques. The cost of controlling termites and repairing their damage is estimated at $2 billion annually in the United States. These losses do not include those incurred by the military or the growing impact from the Formosan termite. Termite control also carries the highest risk for the pest control industry of all categories in urban pest management, and increasing restrictions on insecticides make their control less reliable and more costly. For these reasons, this problem area is a high priority. It can be divided into research originating from scientists within the unit and research originating from outside the unit through agreements with industry. Internal studies conducted during 2000 included research on the distribution and fate of termiticides in soils, the temporal and spatial effects of insecticides on foraging behavior, and the effects of sub-lethal dosages of chemicals on gut protozoa of termites. We found that boric acid negatively affected symbiotic protozoa in termites, and native termites were more susceptible to boric acid than Formosan termites. These results support the finding that borate wood preservatives suppress termite damage. An ongoing cooperative study conducted in the U.S., Australia, and Thialand found that the type and concentration of wood preservative affected the ability to protect against termites. Compound success was consistent across sites. Problem Area 2: Biology, Ecology and Behavior. Conditions regulating native subterranean termites in natural habitats are poorly understood, and in 1999, research was initiated to investigate the biological, ecological, and physical parameters associated with the diversity and distribution of termites in forest ecosystems. This research will provide an understanding of the habitat requirements supporting and promoting each species. It will furnish insights required to initiate more complex studies on termite colony, population, and community dynamics, which will support the development and implementation of improved integrated treatment strategies directed against termites. Knowledge from these studies may be used to develop risk assessment tools for individual termite species in residential areas. To this end, termites were collected and mapped along with other site information from 370 diverse locations during 1999-2000. Identifications of termites are proceeding, with a possible new species found. A graduate student will begin work this year on termite identification (species, colony, and population). Wood decay fungi were also collected and cultured for assessment of behavioral or foraging affects on termites. In another study, a direct relationship was found between temperature and respiration rates in worker termites, with workers exhibiting higher respiration rates than nymphs and soldiers. Problem Area 3:
Role of Termites in Nutrient Cycling.
In response to the changing mission of the Forest Service, the project
has initiated cooperative research to investigate the role of coarse woody
debris decomposition in sustaining long-term soil productivity of managed
loblolly pine in Mississippi and Texas. Coarse
woody debris is important in soil transport, sediment storage, energy nets, and
nutrient cycles in forest ecosystems. Our
understanding of the processes governing sustainable productivity is
rudimentary, and our knowledge of the role of woody debris decomposition in
maintaining long-term carbon and nutrient capital of the soil is minimal.
Few studies on wood decomposition have been carried out in managed
southern pines. A long-term study
has been installed that will examine the decomposition rates of loblolly pine
and the biotic and abiotic factors affecting the decomposition process,
including the role of termites. This
study will produce guidelines for managing woody debris in the context of
sustaining enhanced productivity of managed loblolly pine. Cooperative research in young loblolly pine plantations
continued with a long-term soil productivity study at the same sites.
The relationships among termite species, soil compaction, and organic
matter removal are being examined. More
termites were found in Mississippi than Texas.
In Mississippi, more termites were found at monitoring stations in plots
with highly compacted soils compared to plots with no compaction.
Organic matter removal did not influence termite numbers. Fewer termites were found in the control plot (mature pine
stand) compared to the treated plots. Although
not statistically significant, more termites in Texas were found in plots with
the most organic matter removal compared to plots with the least, and soil
compaction did not influence termite numbers.
A greater number of termites were found in the control plot compared to
the treated. These contrasting
results are under investigation. In
general, termite numbers increased during the late winter and spring, whereas
damage lagged slightly behind and was greatest during the spring and summer. Problem Area 4:
Formosan Subterranean Termite. This is an emerging area of importance
to the Forest Service. The Formosan subterranean termite is an exotic pest
causing about $1 billion damage in the U.S. Unlike native species, this
aggressive termite attacks living trees, potentially threatening southern
forests and the urban/forest interface. Potential damage to forests is
twofold: direct damage or death to trees and indirect disruption or
displacement of native termite species which promote wood decomposition and
nutrient cycling and, thus, forest ecosystem health and productivity.
Demand for product testing aimed at this pest has increased.
Unfortunately, no new research has been initiated on Formosan termites due to
the lack of funding. we are continuing physical barrier and termiticide
research on this pest in cooperation with the U.S. Fish and Wildlife Service on
Midway Island. We have also investigated opportunities to secure funding
to develop contacts with foreign investigators. |
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