2009 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) Re-invasion study: More than twenty colonies of FST in Armstrong Park, which is located adjacent to the New Orleans French Quarter, have been eliminated. The re-invasion 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 the 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.
Armstrong Park Project: Following the total elimination of all detectable Formosan subterranean termite (FST) colonies in 2004, the number of active monitoring stations increased slowly from 3 in 2004 to 22 stations in 2006. By the end of 2007, the number increased to 55 stations and reached its peak of 122 stations by September 2008. The rapid growth period was observed in 2007 and 2008, 3-4 years after the total elimination. More data is needed to confirm if we have reached the plateau. One significant observation was made in July 2008 when live FST were found in 3 stations on the isolated island. It took 4 years since the total elimination in 2004 to detect FST activity in the island. This confirms our previous assumption that it may take 3-4 years for an alate pair (winged form) to grow into a population large enough to be detected. Termite Biology Project: Antifungal activity of norharmane, (a chemical found in termite), was tested against 2 types of fungi that cause disease in insects, (Metarhizium anisopliae & Aspergillus nomius). It was determined that at physiological concentration, norharmane had no significant effect on A. nomius growth rate, but reduced M. anisopliae growth rate by 11.9%. Contrary to previous findings, we suggest that norharmane has a limited role in disease resistance against fungal pathogens in individual subterranean termites, but may play a role at a colony level. FST is primarily reported from subtropical and warm temperate regions while the Asian subterranean termite, C. gestroi, is reported from many areas of the tropics. Taiwan is one of a few areas where the distributions of the 2 species overlap. By analyzing partial molecular genetics, we found that most Taiwanese FST populations were closely related to Japanese and some Chinese populations, and that Taiwanese termite populations were most closely related to those from the Philippines and Hawaii, rather than populations from Thailand, Malaysia, Singapore and Indonesia. The results support that Taiwan may be a center of origin for FST, but a recent introduction site for C. gestroi. A model of tunnel excavation was proposed that requires no pheromone (a chemical attractant secretion) labeling of soil or work sites, but instead relies on tactile interactions and individuals who actively orient their movement. Potential termite excavators moved from the tunnel origin towards the far end of the tunnel and formed a queue behind those termites at the digging face. Delayed termites excavated soil laterally from the tunnel wall at a position governed by their position in the queue of termites. By examining excavation under artificially induced conditions of longer and shorter queues of termites at the tunnel end, we showed that tunnel width increased with increased queue size and the rate of lateral excavation in a process we termed “digging pressure.” Progress of this project is monitored through Annual FST Technical Committee Meetings, reports, regular meetings with cooperators, routine phone calls, and e-mail correspondence.