EFFICACY OF CONVENTIONAL INSECTICIDE AND JUVENOID MIXTURES ON AN INSECTICIDE-RESISTANT FIELD POPULATION OF GERMAN-COCKROACH (DICTYOPTERA, BLATTELLIDAE)

Insecticide and juvenoid mixtures were evaluated for 12 mo in the fiel d against an insecticide-resistant field population of the German cock roach, Blattella germanica (L.), in infested apartments. Treatments co nsisted of three mixtures: (1) Empire 20(R) and Gentrol(R) (i.e., chlo rpyrifos and hydroprene); (2) Commodore(R), Nylar(R), and PBO-8(R) (i. e., lamdacyhalothrin, pyriproxyfen, and piperonyl butoxide); and (3) D iacap 300CS(R) and Torus(R) (i.e., diazinon and fenoxycarb). Sticky tr ap catch was used to monitor population numbers, and there were no sig nificant differences between treatment regimes at any pre-or posttreat ment evaluation periods. Trap catch reductions increased throughout th e study to 95.3%, 90.7%, and 85.3% at the end of the test for Empire, Commodore, and Diacap treatments, respectively. Percentage of wing twi st (an indicator of juvenoid-induced sterility) increased over time an d reached over 80% at 6 mo for all treatments. In addition, the ratios of nymphs to adults (an indicator of population productivity) and gra vid to nongravid females (a measure of population fertility levels) we re reduced by all mixtures. Results of this study indicate the potenti al usefulness of mixtures of conventional insecticides and juvenoids i n integrated pest management and resistance management programs for th e German cockroach.