Chemical Termite Barrier
Chemical Termite Barrier and why they are not a DIY project.
Efforts to control subterranean termite infestations inside structures have traditionally depended heavily on liquid chemical termite barrier applications. These applications consist of trenching around the perimeter of a structure and/or drilling holes at given intervals into the foundation block and slabs (Rambo 1985).
The traditional chemical termite barrier was both very persistent in the soil and extremely repellent to termites. However this persistence also created risks for the applicator and the home owner, ultimately resulting in their removal from the market.
Repellent Chemical Termite Barrier
The introduction of newer chemical termite barriers which also are intended to serve as a defensive barrier between the termites in the soil and the structure above ground, repelling worker termites from tunneling toward the foundation, however they lacked the potency of previously used chemical termite barriers, creating the need for much better application. Finally, the active ingredients in the newer liquid chemical termite barrier degrade much quicker over time in the soil and have to be reapplied, often annually (Mauldin et al. 1987).
Further the newer repellent liquid chemical termite barriers have been shown to have several other limitations. For example, liquid chemical termite barrier applications are limited by the type of soil found near the structure. Sandy soils accept chemical termite barrier solutions readily, but depending on the particle size of the sand, the chemical termite barrier may not spread evenly beneath the soil to give a continuous barrier (Rambo 1985). The behavior of liquid chemical termite barrier in clay soils also varies with its consistency. Many clay soils are too compacted to receive chemical termite barriers and must be roded at narrow intervals to provide chemical termite barrier overlap beneath the soil surface (Rambo 1985). Likewise, loam soils also vary in degree of compaction. Because organic matter interferes with the distribution of the chemical termite barrier in the soil, all organic matter present reduces the chances of achieving a continuous barrier in the soil (Rambo 1985).
Non-Repellent Chemical Termite Barrier
The regular failure of newer repellant chemical termite barriers resulted in the introduction of even newer liquid chemical termite barriers, with active ingredients such as fipronil and imidacloprid, which are non-repellent and work to kill termites with delay upon contact (Kard 1998, 2000; Gahlhoff and Koehler 2001; Thorne and Breisch 2001).
The initial evidence indicated that termites exposed to sub lethal doses of these non-repellent chemical termite barriers can even transfer the toxicant to other nestmates (Clement 1998; Thorne and Breisch 2001).
However, Saran and Rust (2007) concluded from their studies that the perception by the pest control industry that the delayed toxicity and non-repellency of the newer termite control chemicals are responsible for areawide control of termites is false. Saran and Rust showed that only very limited control occurred and the need for full barriers remained. They found that at high concentrations the non-repellent chemicals still worked as repellents and at low enough concentrations for potential colony control, the mortality rate was so low that the barrier risked failure.
Saran and Rust (2007), found that control of termite colonies was extremely difficult using liquid chemical termite barriers and the transfer of lethal doses between recipients. If sufficient toxicant is to be transferred to recipients over distances by exposed termites, the toxicant must exhibit delayed toxicity. To exhibit delayed toxicity there is a very narrow range of doses (Concentration X Exposure Time) over which such transfers might occur in field situations. Thus horizontal transfer is only a minor contributing factor to the efficiency of non-repellent chemical termite barriers in the field.
Edward L Vargo AND Vincent Parman (2012) in a study supported by the actual chemical company of the non-repellent chemical termite barriers tested found the complete cessation of activity in the inner monitors after treatment. They suggested that the area immediately around the structure remained largely or completely termite free within 90 days of treatment. However as is the case with Bait trials when termite mound colonies are used and the physical evidence of destruction can be witnessed, this is not the case with this trial and simply the lack of foraging termites is extrapolated to argue for colony elimination. They argued some 25% of the likely treated colonies survived and persisted throughout the study period, however how they concluded this quantity is unclear.
Thomas G Shelton (2013) in contrast found small plots of Fipronil-treated soil did not cause termite feeding to cease in any area surrounding the treated plots within a year after treatment.
In conclusion, the effectiveness of the newer chemical termite barriers, both repellant and non-repellant is very dependent on application. The majority of independent studies would conclude that all chemical termite barriers have little effectiveness in controlling termite colonies and work to fence out attacking colonies rather than any long term termite control. Without the necessary training and skill level the application of chemical termite barriers as the only method of home protection from termites is not recommended.
However it is not necessary to understand the extremely technical aspects of dose and application OR even place chemicals anywhere near you or the environment, in fact the Termite Mansion is the first design where no active ingredient comes anywhere in contact with the ground, with termites feeding in a completely isolated feeding chamber.https://termitemansion.com.au/how-does-it-work/
Why pump liters of active ingredient into the environment when its effectiveness and harm is so unknown? When the effectiveness of Baiting has been so widely proven, when less than a gram of active ingredient is used to completely destroy the colony threat for good rather than temporarily repel termites, why risk your home and family?