Adult Control I
Adult Control I
The Bottle Bioassay (BB), developed by the Centers for Disease Control (CDC), is commonly employed to characterize insecticide resistance levels of mosquito populations in laboratory environments. The BB versatility is remarkable; it can be used with different species, lab or field-acquired strains, and a variety of different insecticidal active ingredients or formulations. As an established assay, the BB is widely utilized by mosquito control professionals throughout the country and world; however, few studies have established a clear correlation between BB outcome and semi-field and/or field mortality. Most correlations between the BB and operational control activities are anecdotal, despite the need for a standardized correlation method. As part of ongoing discussions with the National Insecticide Resistance Working Group and the Northeastern Center of Excellence in Vector-borne Diseases, we employed a new method to compare previously obtained CDC Bottle Bioassay data and semi-field mortality results. Mean lethal times (MLT) were obtained using Kaplan-Meier survival analysis for different BB strain/insecticide combinations. The analysis was performed on over 15 strain/insecticide combinations for which matching semi-field trial data (truck mounted ULV spray trials) was available. Our initial results show that mean lethal times were remarkably similar on the same strain/insecticide combination, even when mosquitoes were assayed on different days demonstrating the robustness and consistency of the analysis method. MLTs were then correlated with semi-field mortality data across different times and distances from ULV spray transects. Strong correlation (r = 0.78, p-value=0.002) was observed at one distance and time (300-ft, 12 h) compared to the BB MLTs for matching strain/insecticide combinations. These results demonstrate the potential utility of this novel analysis in predicting semi-field/field results. Moreover, the MLT analysis requires minimal modifications to testing regimens, making it practical for mosquito control professionals to adopt.