Laboratory evaluation of AI3-37220, AI3-35765, CIC-4, and deet repellents against three species of mosquitoes

Four repellents, N,N-diethyl-3-methyl-benzamide (deet), 2-hydroxy-methyl-cy clohexyl acetic acid lactone (CIC-4), and 2 piperidines (1-[3-cyclohexen-1- ylcarbonyl] piperidine [AI3-35765] and 1-[3-cyclohexen-1-ylcarbonyl]-2-meth ylpiperidine [AI3-37220]) were evaluated alone and in combination against A edes aegypti, Anopheles stephensi, and Culex quinquefasciatus using a modif ied in vitro test system. This method was a valuable tool for comparing eff ective concentrations of the new compounds. Because of the controlled condi tions of the test, it was possible to use the results of assays that had be en conducted over a 5-year period and to perform the many replications nece ssary to evaluate combinations of compounds. The new candidate repellents w ere generally as effective as deet. Although speculative at this time, ther e was some evidence of synergistic interaction. Repellent combinations of C IC-4/AI3-37220/AI3-35767, deet/AI3-35765, and deet/AI3-37220/AI3-35765 agai nst An. stephensi and CIC-4/AI3-35765, deet/AI3-37220/AI3-35765, AI3-37220/ AI3-35765, and CIC-4/AI3-37220 against Ae. aegypti were more effective than the component compounds alone.