103 - Recreating ULV Sprays in the Lab to Evaluate Adulticide Formulations

Abstract: Knowing which insecticide to apply to control adult mosquitoes is crucial for successful Integrated Mosquito Management. The wrong product can waste money and time and even more importantly, fail to protect the public from being bitten by nuisance and the disease transmitting mosquitoes. There are several ways to try and determine which pesticide may work best for controlling adult mosquitoes with ULV sprays, but each has shortcomings. Semi-field trials with caged mosquitoes can do a good job at well a product does at controlling mosquitoes in the field with real spray conditions. However, these trials are very time consuming to set up, and greatly impacted by environmental conditions, making them hard to repeat and difficult to test many different products. At the other end of the spectrum there are CDC Bottle Bioassays, which can help determine if there is resistance to a specific active ingredient, yet they do not show which products work the best when sprayed in the field. Topical assays can be used with formulated products to also determine resistance levels and can have the benefit of using actual products, but the application method is very different from a ULV spray. To work in the middle ground, we developed a wind tunnel that allows for ULV sized droplets of formulated product to be sprayed on mosquitoes. The wind tunnel uses pesticide diluted at similar rates to those in field labels using an airbrush gun controlled by servo motor. Replicates were easy to perform. We were able to test 7 different products, each at 3 different rates. Results showed large differences in efficacy of the various products against our field collected Culex tarsalis mosquitoes.