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Larvicide Resistance: Investigating and Adapting to an Emerging Threat Symposium

Larvicide Resistance: Investigating and Adapting to an Emerging Threat Symposium

36 - Spatial and Temporal Trends in Larvicide Use in Florida: Implications for Mosquito Resistance Management

Tuesday, March 4, 2025

1:57 PM – 2:09 PM AST

Location: 208 B

Abstract:

Mosquito-borne diseases pose significant public health threats, requiring effective vector control strategies. In Florida, larvicides play a crucial role in controlling mosquito populations, with increasing concerns about the development of resistance. To analyze the spatial and temporal trends in larvicide use in Florida, we collected larvicide usage data from the Florida Department of Agriculture and Consumer Services for each county for select years between 2013 and 2023. Arbovirus surveillance data were sourced from the Florida Department of Health, and metropolitan versus non-metropolitan areas were classified based on U.S. Department of Agriculture definitions. Color-graded maps were created in ArcGIS Pro. Visual comparisons were made of larvicide use across different counties and years, alongside their respective arboviral case reports and the status of metropolitan versus non-metropolitan areas. Our findings show a significant increase in biorational larvicide use, with Bacillus thuringiensis israelensis being applied in 38 counties in 2013 and 42 in 2023, and Bacillus sphaericus increasing from 25 to 34 counties over the same period. Spinosad use nearly doubled, while methoprene remained consistent, and temephos use declined significantly. Local arbovirus transmission likely influenced larvicide application, with all counties reporting local arbovirus cases in 2022 applying larvicides. Notably, Suwannee County had no larvicide use or arbovirus cases in 2013 and 2022 but applied larvicides in 2023 potentially due to an Eastern equine encephalitis case. Additionally, metropolitan areas used more larvicides than non-metropolitan areas. These results show an increase in larvicide use over the years. These findings highlight the urgent need for further research on larvicide resistance to ensure the continued effectiveness of mosquito control interventions.

Presenter(s)

Raquel Lima de Souza, PhD

Postdoctoral Researcher Associate
University of Florida, Florida, United States

Co-Author(s)

Eva Buckner, PhD

Assistant Professor and State Extension Specialist
University of Florida, Florida, United States