Toxicity of Imidacloprid Bait to Microcerotermes diversus (Silvestri) (Isoptera: Termitidae) under Laboratory Conditions

Microcerotermes diversus (Silvestri) is a major pest of buildings and a wide variety of crops and trees in Khouzestan province, because of consuming on materials containing cellulose. One new environmentally safe tactic for the control of subterranean termites is baiting world-wide. In laboratory bioassays, toxicity of imidacloprid bait at concentrations of 25, 50 and 100 ppm, was evaluated under choice and non-choice feeding conditions. A probit analysis of the data using time instead of dosage indicated that the level of mortality and the speed of death were dependent on dose. An inverse relationship between time mortality (LT50 and LT90) and dose was observed. Total feeding inhibition was not observed in any concentration although feeding decreased with increasing of imidacloprid concentration. In choice trials, termites preferred baits over wood and filter paper. cellulose bait impregnated with imidacloprid at a concentration of 100 ppm elicited high mortalities after 7 days in non-choice and choice trials (97% and 89%, respectively). Overall, the results indicated that imidacloprid bait is effective for controlling M. diversus and the baiting tactic may present a suitable approach for protecting structures from termite attack in Iran.