Control of container mosquitoes with triflumuron in key urban land uses and effects on non-target dipterans

Abstract

Mosquitoes are of major public health importance throughout the world. Recently, there has been an increase in mosquito-borne diseases some of which are newly emerging, and some are remerging. Chemical control remains the main approach to reducing mosquito vector populations, therefore mitigating the transmission and spread of mosquito-borne diseases. Urban land uses have been identified as highly productive for container mosquitoes and thus require vector control interventions. In this study, we compared the effectiveness of the larvicide triflumuron in controlling mosquito vectors in households, cemeteries and tire shops and assessed its potential impact on non-target dipterans in urban temperate Argentina. On average, treatment with triflumuron reduced the occurrence of Aedes aegypti by 81% and Culex pipiens by 45%, with no significant differences among land uses. Two-thirds of the containers with these two mosquito species also harbored at least one non-target dipteran species (other Culicidae, Chironomidae, Psychodidae, Ceratopogonidae, Phoridae, Ephydridae, Syrphidae and Sciomyzidae). Triflumuron application also had unintended effects on non-target dipteran communities, resulting in reduced richness and diversity across all land uses, as well as a reduced density of individuals in tire shops. Triflumuron proved highly effective against Ae. aegypti and moderately effective against Cx. pipiens regardless of land-use patterns. However, unwanted effects against some non-target accompanying Diptera fauna were also recorded, suggesting a severe limitation for the use of this larvicide in areas where biodiversity conservation is of paramount importance. Preserving biodiversity and human welfare must be a primary goal in the search for better vector control measures.