Honey bees (Apis mellifera) are arguably the most important beneficial insect in agricultural and horticultural ecosystems in the United States. Despite their importance, honey bee populations have been negatively impacted by a number of factors, including disease, pests, and exposure to pesticides. Some of these pesticides are used to control mosquitoes, which are both a nuisance and a vector of human and animal diseases. Therefore, public health districts have been established around the U.S. to control mosquito populations through the controlled application of insecticides. Spray drift is a common concern when applying pesticides, particularly with regard to deposits onto highly sensitive unintended targets, such as waterways and honey bee hives. Drift modeling is available for most sprayer models and application techniques, but the truck-mounted spray systems used in public health insect control have much fewer options. The fate and risk of commonly-used public health insecticides in waterways was evaluated in a literature review. Not nearly enough is known about these pesticides and their chronic and sub-lethal effects or their potential combined effects. Urban runoff is often much more contaminated than agricultural runoff due to lack of monitoring and higher application rates per unit area. The impact of commonly-used public health insecticides used for mosquito control on honey bee mortality was assessed. The insecticides tested had negligible impact on honey bee mortality even at maximum usage rates. Applicators should still use these products with caution when making public-health applications in areas around apiaries because chronic and sub-lethal effects were not tested. AGDISP(R) with inputs that emulated a field study setup was used to determine drift from a public health insecticide sprayer. Once the model was validated for this kind of application, the model and the inputs were then used to determine depositions and concentrations at various distances from the spray swath. The deposition and concentration values were then compared to available honey bee and aquatic toxicity values for the specific products in question. These comparisons showed that in these conditions, buffer zones were not needed for these products.
