P-15 - Assessing Minimum Risk 25(b) Products for Control of Blacklegged Ticks in the Upper Midwest, USA

Abstract: In the United States, Lyme Disease is the most common vector-borne disease reported annually. There is an urgent need to control the vector, the blacklegged tick (BLT), Ixodes scapularis, in peridomestic settings to prevent transmission to people and pets. Synthetic acaricides are available for use to homeowners as do-it yourself treatments, or through contract services with commercial pest control companies. However, due to the perceived negative impacts of synthetic pesticides on the environment and human health, people are increasingly looking for “natural” alternatives for use to control pests in and around their homes. Essential oil-based products are one of these alternative options that are widely marketed as a “green” alternative for vector management. These minimum risk 25(b) pesticides are exempt from registration with the United States Environmental Protection Agency and, therefore, the validation of efficacy that comes with such registration. We set forth to characterize the effectiveness of 25(b) essential oil-based products for BLTs from the Upper Midwest, USA, in laboratory and field conditions. We adapted an immersion assay to rapidly screen 25(b) products for toxicity to nymphal BLTs from a newly established colony from Wisconsin, USA. To test the effect of these products on nymphal BLTs in the field, we compared the effects of a 25(b) product, a synthetic pesticide, and water alone, as applied using a Stihl SR200 backpack sprayer. These studies were conducted at a site with a high density of nymphal BLTs in Richland County, WI, USA, during the month of June, 2024. The 25(b) product tested in this study provided limited and short term nymphal BLT control as compared to the synthetic pesticide. This work provides a roadmap for screening 25(b) products for tick control in peridomestic settings.