144 - Pilot field trials of freeze-dried beets as an oviposition lure for Aedes aegypti in New Orleans, Louisiana, USA

Abstract: Aedes aegypti is a primary vector of many human pathogens, widely distributed throughout the tropics and is continually invading new areas. Ovitraps are crucial in surveillance programs for container-breeding species like Ae. aegypti, but their efficacy is reduced by competition with other water containers and skip-oviposition behaviors of this species. Researchers have found that the geosmin in beets may serve as an efficient and cost-effective lure for Ae. aegypti ovitraps. We tested encapsulated freeze-dried beet peel and beet pulp in two ovitrap conditions during pilot field trials in New Orleans, Louisiana, over ten weeks in summer and fall 2024. In the first trial, a twelve-block section of the city was chosen, aiming to enroll two houses per block. Ultimately, 21 sites were used, with three ovitraps at each site: (1) control, (2) beet pulp, and (3) beet peel. Eggs deposited on seed germination paper within the trap were counted using ImageJ after scanning. In the second trial, three sites from distinct census tracts were selected and sampled for four weeks with four attractive lethal ovitraps, minus the insecticide: (1) control, (2) beet pulp, (3) bacterial attractant beads, and (4) beet pulp + bacterial attractant beads. After counting, all eggs were hatched and reared to the adult stage for species identification. All traps in both trials were checked weekly, and the ovitraps were moved within each site according to a computer-randomized schedule to control for trap placement effects. Traps with any beet preparation had significantly more eggs than control ovitraps. Positional effects of trap placement were observed, indicating that appropriate ovitrap placement is essential for maximum egg yield, regardless of the use of an oviposition attractant. This pilot trial demonstrated the utility of encapsulated freeze-dried beet preparations as oviposition lures for Ae. aegypti in a tropical environment.