When baiting the more challenging species of termites, it is wise to use a bait that has been shown to achieve colony elimination.
Australia’s mound-building termites fall into two main families: Rhinotermitidae, referred to as the lower termites, which includes Coptotermes spp.; and Termitidae, the higher termites, which includes Nasutitermes spp. and Microcerotermes spp. The higher termites are evolutionarily the most specialised termite group, with their gut having a high capacity to degrade lignocellulose. The workers of higher termites don’t moult and they are also fungal feeders, which makes them more difficult to control by termite baiting.
With these mound-building species, the mound typically consists of a thick outer wall that covers the inner part of the nest. A peripheral space is also present between the protective outer wall and the inner nest. This inner nest contains the nursery zone, where the eggs and most of the larvae are found, and the royal chamber, where the king and queen(s) are found. This area is deep within the mound, with the royal chamber located in the centre. In addition to the royal pair, it contains small access openings for workers.
Termite baiting is a preferred option for termite management with many professional pest managers. In the field though, most pest managers can only determine if a baiting treatment has worked based on the absence of termite foragers or the cessation of termite feeding activity in monitoring stations. Since the mound is rarely found, it is important for pest managers to have confidence that the bait has actually eliminated the colony.
This means that when treating mound-building termites, it is necessary to use a termite bait that has been proven to be successfully transferred from the workers to the rest of the colony, especially the brood and queen in the inner part of the nest.
Steve Broadbent, regional director for Ensystex, advises that, “Exterra Requiem Termite Bait has been proven to eliminate colonies of both the lower1 and higher2 termite species through many, peer-reviewed, published studies, all confirming the ability of Requiem to eliminate the colony. This gives professionals added confidence in determining colony elimination.
“The key to the success of a termite bait in the field lies in its palatability and ability to be transferred throughout the colony, and in a sufficient amount to be transferred back to the colony to eliminate it. This is where we believe Requiem to be unique, the specifics of the cellulose used in the formulation enable greater feeding on the bait, to better achieve colony elimination efficacy, as confirmed by the large number of peerreviewed studies completed (e.g. Rawat 2010, Peters, Broadbent and Dhang 2008).
“In many of these studies the location of the colony was identified and, after remote indications of colony elimination were identified, the actual colony was dug up to confirm all termites, including the reproductives were eliminated.”
The ability to measure the amount of toxicant transferred between termite individuals is crucial in assessing successful colony elimination through termite baiting. In a 2013 study, the use of a simple and sensitive assay using GC-MS to determine the presence of the active component of Requiem in termites has further confirmed the ability of Requiem to transfer quickly through the colony,3 which helps instil further confidence in professional pest managers using the Exterra system.
Working with one of the most challenging of the higher termite species, Macrotermes gilvus, in Malaysia, after initially baiting the colony, the team excavated the mound. The termite samples were then collected. During the excavation process, all the workers and larvae were collected from the different parts of the mound (i.e. peripheral zone, nursery zone, and royal chamber). The termites were then assayed for the presence of the Requiem active.
The methodology used confirmed that the Requiem had actually been ingested and transferred among the colony members, and could not have been due to Requiem adhering to the outer body surface of the termites.
The results showed that the concentrations of Requiem detected in workers extracted from the royal chamber were significantly the highest, when compared to that present in workers and larvae from other parts of the mound. In general, the highest amount of Requiem was detected in workers from the royal chamber, followed by workers in the peripheral zone, workers in the nursery zone, larvae in the nursery zone, and larvae in the peripheral zone. The termite workers transferred approximately 5% of the ingested Requiem to the termite larvae.
This study confirmed that Requiem Termite Bait is successfully and quickly distributed throughout the termite colony with the greatest concentration arising in the inner nest and nursery due to the large numbers of workers feeding the Requiem through trophallaxis.
Mr Broadbent added, “Requiem has undergone extensive field and laboratory testing – we don’t just know it works, we also know how it works. This gives pest managers the confidence that when they start to see the visual indicators they know colony elimination is assured.”
1 BC Peters and S Broadbent (2003). Evaluating the Exterra Termite Interception and Baiting System in Australia. Proceedings of the International Research Group on Wood Preservation, Brisbane, Australia. IRG/WP 03-20267.
2 C Lee, CN Manb and CY Lee (2013). Effect of Chlorfluazuron Bait Against Macrotermes gilvus: Evidence for the presence of the toxicant compound in workers and larvae. Proceedings of the 10th Pacific-Termite Research Group Conference S4.1:2.
3 Ching-Chen Lee, Che Nin Man, Norjuliana Mohd Noor, Razak Lajis and Chow-Yang Lee. 2013. A simple and sensitive assay using GC-MS for determination of chlorfluazuron in termites. J. Pestic. Sci. 38(4), 208–213 (2013).
BS Rawat (2010) Studies on Chlorfluazuron 0.1% Based Baiting System for Termite Management in Buildings in India. Ann. Entomol., 28 (2): 83-87.
BC Peters, S Broadbent and P Dhang (2008). Evaluating a Baiting System for Management of Termites in Landscape and Orchard Trees in Australia, Hong Kong, Malaysia and the Philippines. Proceedings of the 6th International Conference on Urban Pests. Budapest, Hungary.