Effects of four chitin synthesis inhibitors on feeding and mortality of the Eastern subterranean termite, Reticulitermes flavipes Kollar (Isoptera:Rhinotermitidae)

Abstract

This study measured changes in feeding and mortality of the Eastern subterranean termite, Reticulitermes flavipes when exposed to diets treated with one of four chitin synthesis inhibitors including; diflubenzuron, triflumuron, hexaflumuron and lufenuron. All were benzoylphenyl ureas (BPUs). The tests included five different concentrations of each. The first objective of this study was to determine the concentration of each of the four different benzoylphenyl ureas that was acceptable to R. flavipes in a food source. The second objective was to observe the effects of these insecticides on R. flavipes in laboratory testing. The third objective was to determine preferences by R. flavipes had when given a choice between treated and untreated cellulose. Evidence of the "jackknifed" pose characteristic of chitin synthesis inhibition, overall mean survivorship and the slope of survivorship were all observed. The results varied with chemical and concentration, but almost all treatments caused more mortality than untreated controls. All treatments resulted in jackknifing of the fed termites. When presented with choices, R. flavipes did not show definitive preferences in a majority of the tests. Lufenuron, a benzoylphenyl urea not yet approved for use on termites, was highly acceptable to R. flavipes. Termites fed on lufenuron also exhibited high rates of mortality. Hexaflumuron and triflumuron showed similar acceptability and mortality at two concentrations tested. Although diflubezuron was acceptable to the termites, they did not show high mortality in the six weeks of observation of this experiment. Lufenuron and triflumuron, two benzoylphenyl ureas that are not yet approved for use on subterranean termites, have qualities that would make them good candidates for use as termite bait toxicants. Lufenuron was especially acceptable to R. flavipes. Termites exposed to this BPU showed a high percentage of mortality.