2011 Annual Report
1a.Objectives (from AD-416)
1) Evaluate and examine the potential and mechanism of re-invasion by FST into vacated foraging territory in Armstrong Park of colonies(s) that were previously eliminated by baits; and.
2)establish an area-wide management project in a small urban community, Poplarville, MS, and in rural forested area, Stennis Space Center, MS, infested community and achieve a sustainable program by colony elimination (population reduction) with less toxic and persistent termiticides.
1b.Approach (from AD-416)
1.REINVASION STUDY:More than twenty colonies of FST in Armstrong Park,located adjacent to the New Orleans French Quarter,have been eliminated. The reinvasion scenario will be monitored with a series of in-ground monitors placed on the perimeter of the park and throughout the foraging territory of the previously eliminated colonies. Alate sticky card traps will be use to monitor the density of the general population of new invaders..
2)Area-wide management: Poplarville, MS, and the Stennis Space Center have been identified for sustainable FST management program. The relatively isolated rural town and an isolated area at the Center are infested with FST, and serve as ideal sites for the project. A preliminary survey indicated multiple populations of FST in the town that can be readily characterized, monitored, and baited. Detected FST populations, thus far include the police department, old railroad station, and a few other residential areas. They will be monitored to determine the density and extent of the infestation with survey stakes in bucket stations and alate sticky traps in key areas of the town to survey the overall FST populations. Commercial bait products or a prototype of the "hermetically sealed bait" will be installed at sites with FST ground activity. Baits will be applied by ARS personnel. If there is a need to involve pest control firms for bait applications, a single firm will be selected for applying baits in a well-defined area. If the anticipated area is too large for a single pest control firm to handle, then a contiguous block of a reasonable size will be assigned to one firm. Bait consumption will be monitored using a modified version of a colony elimination system. Following the bait installation, local activity of FST will be monitored and documented with bucket stations. The overall FST activities in the town will be monitored annually by using the sticky trap survey of alates in the spring.
Following elimination of all detectable Formosan Subterranean Termite (FST) colonies in Armstrong Park in 2002-2003, a re-invasion of FST populations was monitored from 2004 through 2011. FST activity appeared to reach peak in 2008 and remained stable in 2009. FST populations plateaued in 2010 and results showed if baiting program is discontinued, invasions by neighboring colonies and alate pairs will bring the FST population to the level similar to that of pre-baiting period park within 4-5 years. As the final phase of the study, in Sept. 2010, we baited the FST colonies with Recruit HD "always active" baits. Of five colonies baited and eliminiated Colonies #4 & #14 were eliminated by Dec. 2010, #9 by Mar. 2011, #12 by end of 2010, but its territory was immediately occupied by a previously unknown Reticulitermes flavipes (R. flavipes) colony which was subsequently eliminated after consuming Recruit HD baits. Colony #8 located near the park border, began to decline after consuming the HD baits but another FST colony (presumably outside of the park) took over, and it is expected this re-invading colony will be eliminated in the near future. Because AI-containing baits are in place, even the existing colonies are being eliminated; also the re-invading termite colonies will encounter and consume the HD baits and will be eliminated. The continuous eliminations of re-invading termite populations should keep termite populations below damaging threshold. We plan to continue the project for the next few years to confirm this working hypothesis.
Use of a self-replicating virulent agent that can cause an epizootic to kill the entire colony termites has been the major thrust for biological control of termites. However, absence of positive results in field studies challenged the potential of fungal pathogens as a realistic approach for subterranean termite control. This study identified defense mechanisms of subterranean termites to prevent an epizootic from occurring. The mechanisms include three components, grooming, cellular encapsulation, and gut antifungal activity. These mechanisms probably act synergistically to produce an efficient defense against the infection of the fungus at the individual and group level so as to protect the colony from epizootics. FST and Coptotermes gestroi (C. gestroi) are the most widely distributed species of the genus and occur sympatrically in the subtropics. Results of bioassays showed that (C. gestroi) was more aggressive than FST, but when tunnels of species in arenas encountered each other, both species quickly buried the connected tunnel & termite cadavers resulting from agonistic behavior appeared to have induced sand deposition that resulted in tunnel blockages and deterred reopening of these blockages. Sealing individual tunnels in response to encounters with other species acts to prevent further agonism and mortality, and on a broad scale, aggregate of such blocked tunnels may come to define borders between adjacent colonies. Progress is monitored through Annual meetings, reports, conference calls, email and written correspondence.