Estimation of oral toxicity of boron as a bait toxicant and the trophallactic effects between individual members of termite colonies.

IRG/WP 03-10495

B M Ahmed

In recent years, because of the favourable environmental characteristics of boron, researchers in the wood preservation industries have refocussed on the use of boron as a major wood preservative against wood-destroying insects. Currently the greatest use of boron compounds is in remedial treatments. Boron has been found to have slow-acting toxicity against subterranean termites. Because of this characteristic, boron compounds may also be used as termite bait toxicants. The effect of boric acid on an individual donor termite was investigated in laboratory bioassays Trophallactic transfer of boron by these individual termites to other orphaned group of termite workers was conducted and the effects on the recipient groups recorded. It was believed that, this sequence of tests would provide a greater understanding of the carrying ability of ‘bait toxicant’ by individual termites, and allow estimates of the threshold toxicity of boric acid and termite survival rates to be determined. The bait matrix was Eucalyptus regnans F. Muell sawdust impregnated with various formulations of boric acid solutions in the laboratory. The result suggests that the toxicity of boron is dose dependent and it critical for the termites to ingest sufficient amounts of boron. But the mode of toxicity of boron has not yet been fully explained.

Keywords: Laboratory bioassay, subterranean termites, donor workers, recipient workers, Eucalyptus regnans, bait toxicant, boron, trophallaxis, threshold toxicity, boric acid, termite survival rates

Conference: 03-05-18/23 Brisbane, Australia

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