COMPARATIVE TOXICITY OF SELECTED LARVICIDES AND INSECT GROWTH-REGULATORS TO A FLORIDA LABORATORY POPULATION OF AEDES-ALBOPICTUS

Five organophosphates (OPs) (chlorpyrifos, chlorpyrifos methyl, fenthi on, malathion, and temephos), 3 pyrethroids (bifenthrin, cypermethrin, and permethrin), and 2 microbial pesticides (Bacillus thuringiensis s erovar. israelensis [B.t.i.] and Bacillus sphaericus) were tested as l arvicides against a Florida Aedes albopictus population colonized in t he laboratory. In addition, 3 insect growth regulators (IGRS) (diflube nzuron, methoprene, and pyriproxyfen) were evaluated. All OPs, except for malathion, were highly effective as indicated by low LC(90)s rangi ng from 0.0069 ppm (chlorpyrifos) to 0.026 ppm (fenthion); the larvae were considered tolerant to malathion (LC(90) = 1.043 ppm). LC(90) val ues of pyrethroids were: 0.0175 ppm (bifenthrin), 0.0079 ppm (cypermet hrin), and 0.0031 ppm (permethrin). Commercial products of B.t.i., Vec tobac(R) and Bactimos(R) were considered economically effective agains t Ae. albopictus larvae but products of B. sphaericus were ineffective (LC(90)s > 28 ppm). The IGRs showed exceptional activity. Pyriproxyfe n (LC(90) = 0.000376 ppm), was 2.23 and 21.5 times more toxic than dif lubenzuron and methoprene, respectively. In general, toxicity ranking of chemicals and microbials tested was: IGRs > pyrethroids > OPs > mic robials.