Semifield evaluation of autodissemination systems in Aedes notoscriptus and Culex quinquefasciatus and laboratory analysis of In2Care formulation effects

Abstract Urban mosquito control needs targeted tools that suppress population breeding in cryptic container habitats while reducing reliance on broad-spectrum insecticides. Autodissemination devices exploit oviposition behavior to transfer the insect growth regulator pyriproxyfen to larval sites and may be enhanced by adulticidal agents such as the entomopathogenic fungus Beauveria bassiana. We compared semifield efficacy of In2Care® Mosquito Stations and INZECTO Mosquito OviTraps + INZECTO pyriproxyfen chips against Aedes notoscriptus and Culex quinquefasciatus. We subsequently quantified the adult survival effects of pyriproxyfen, B. bassiana, and their combined formulation (In2Mix) in Ae. notoscriptus. Semifield trials used 4 × 4 m mesh tents in replicate blocks; 50 females per tent were exposed to In2Care stations, INZECTO OviTraps + INZECTO pyriproxyfen chips, or untreated controls with four surrounding oviposition cups. Cup water was bioassayed for emergence inhibition and analyzed with beta-binomial GLMMs. Adult females were force-exposed to treated nettings (pyriproxyfen-only, B. bassiana-only, In2Mix, control) and survival was analyzed with Cox regression. In semifield trials, In2Care reduced adult emergence relative to controls (logit estimate = 1.892, P 0.0001) and was more effective than INZECTO (estimate = −0.990, P = 0.024); INZECTO also reduced adult emergence compared to controls (estimate = 0.902, P = 0.041). In laboratory assays, B. bassiana substantially increased mortality hazard (HR = 7.26). The In2Mix treatment produced a comparable effect (HR = 8.64), suggesting that most of the observed mortality in the combined treatment is driven by the B. bassiana component. Pyriproxyfen alone also significantly elevated mortality risk relative to the control, although the effect size was more moderate (HR = 2.35).