TERMITE BAIT SCREENING USING NATURALLY-INFESTED TREES

Abstract:
Bait toxicants were evaluated against Formosan subterranean termites infesting 61 river-bound trees in Lake Charles, Louisiana. This afforded a natural setting from which termite colonies could not escape and bait efficacy could not be misinterpreted by colony movement away from the study site. Of 12 toxicants studied, only hexaflumuron, mirex, and sulfluramid, eliminated tree-infesting termite colonies. Food consumption and colony die-off varied with toxicant studied and time of year evaluated. Most toxicants evaluated proved to be ineffective at colony elimination at the concentrations tested. Site fidelity of forager groups may account for differences in toxic versus untreated bait consumption in the field. Nochoice tests on sulfluramid baits in the laboratory showed a reduced feeding when compared with untreated bait consumption, though toxicant consumption increased with increasing bait-toxicant concentrations. Thirteen trees in New Orleans baited with only untreated cardboard rolls for 16 months proved that cardboard consumption significantly varied by month. Bait consumption rate was at its lowest during winter months and at its highest rate just before the swarming period in April.