FIELD ASSESSMENT OF AUTODISSEMINATION OF PYRIPROXYFEN BY CONTAINER-INHABITING AEDES MOSQUITOES IN FLORIDA

Abstract

Domestic mosquito control for container-inhabiting Aedes vectors of Zika, chikungunya, yellow fever, and dengue viruses is challenging, and novel methods are needed. Autodissemination strategies are one such method. In this control method, females are attracted to stations treated with an insect growth regulator (IGR), become treated, and subsequently deposit the IGR in natural oviposition sites, preventing pupal emergence. We developed and tested treatment stations in semi-field conditions based on number of captured mosquitoes in the treatment stations. The modified treatment station attracted gravid females with oak leaf infusion and mosquito passage through exit chutes granted access to sucrose and topical contamination of IGR (pyriproxyfen) for 25% of released mosquitoes. Although a majority of released mosquitoes were uncaptured (75%), sufficient amounts of pyriproxyfen contaminated female mosquitoes to result in 75% inhibition of adult emergence in larval bioassays. These stations were then used in a field experiment to test the efficacy using sentinel cups with mosquito larvae. Three treatments which included varied numbers of autodissemination stations (control, low density, and high density) were compared. Both low and high density of stations provided high inhibition of adult emergence from sentinel cups relative to controls. We did not observe differences in mosquito emergence inhibition whether sites contained low or high densities of stations (i.e., similar rates of mosquito inhibition). Two additional field trials showed that topically contaminated mosquitoes were traveling further than expected and causing mortality in sentinel cups at least as far as 80 meters from the autodissemination stations. The development and implementation of autodissemination of IGRs is an additional tool for use in integrated mosquito management.