13 - Use of a pyriproxyfen-based larvicide in Chicago area catch basins

Abstract: In 2021, an assessment of a pyriproxfen-based larvicide, Sumilarv® 0.5G WSP, was performed in a small sample of 60 catch basins within the Chicago area North Shore Mosquito Abatement District (NSMAD). The percent of pupae successfully emerging from catch basins treated with a 1, 2, or 3 WSP-dose (25, 50, and 75 g respectively) was recorded and used to assess effective duration. Based on the results of this smaller experimental study in 2021, the 3 WSP-dose was applied operationally to more than 20,000 NSMAD catch basins in 2022. Back checks performed by NSMAD staff members during the 2022 season to more than 550 of these basins indicated that the applied dose was achieving the expected control within catch basins. A concurrent assessment of the methoprene-based extended-release Altosid XR Briquet®, a product used in Chicago area catch basins for over 30 years, was also performed in 2022 to provide a comparison of effective duration.