With insecticide resistance remaining on the forefront of operational mosquito control districts all over, it is important to implement resistance management strategies. Constant surveillance of current insecticide resistance levels in your local mosquito control populations ensures effective control. Aedes aegypti resistance in Florida is nothing new. Genetic and phenotypic studies have shown that local populations throughout the state have decreasing susceptibility levels to a variety of adulticides. With a limited toolbox of products to choose from, product rotation can be somewhat challenging. Monitoring the efficacy of available adulticides and larvicide products, and application methods in field trials, can give us key insights into the efficacy of a specific product against a specific population.
With the prevalence of mosquito insecticide resistance, finding effective control strategies is extremely vital to having a successful integrated pest management program.
Take a look at this trial that was conducted in Manatee County Florida in order to address these resistance issues by applying a biological larvicide to target a resistant strain of Aedes aegypti in Cortez, Florida:
2020 WALS Evaluation
In the summer of 2020, Manatee County Mosquito Control in Palmetto, FL evaluated WALS strategy with the truck-mounted A1 Super Duty Mist Sprayer and VectoBac WDG against Aedes aegypti at 0.5 lb/acre. The study was conducted in Cortez (Manatee County), Florida, USA (27° 27’ N, 82° 40’ W). The first study site was the untreated control, which was 55 acres, and the second study site was the treatment site which was 57 acres. These locations were chosen because historical data has shown high populations of Ae. aegypti based on weekly ovitrap surveillance. Weekly BGs and ovitraps (10–15 traps/site) were deployed to monitor adult population dynamics. A total of 50 bioassay jars were placed in the field each afternoon of the Bti application (8 application events) at fixed locations to collect droplets and gauge efficacy. There was significant reduction in female adults (P = 0.0002) and landing rate counts (P = 0.0058) as a result of treatment. Larval bioassays during the eight applications confirmed Bti deposit in a variety of coverage types regardless of placement in the yards.
Data provided by Katie Williams, Technical Development Specialist at ADAPCO, previous Senior Research Biologist at Manatee County Mosquito Control District.