275 - Evaluation of Altosid XR, Tekko 0.2G, and 0.5G for Culex larval control under field and semi-field conditions in suburban Cook county, IL

Abstract: In the summer of 2023, we evaluated Altosid XR (S-Methoprene), Sumilarv 0.5G sachets (Pyroproxyfen) and Tekko 0.2G (Novaluron) for control of Culex emergence from stormwater catch basins (field) and in 77-gallon barrels (semi-field) in the NWMAD. Twenty catch basins were treated with one of the three IGRs (n=60 catch basins). Each week 3 dips were taken per catch basin, and all pupae were counted and put in 355 ml clear plastic cups with lids. Every day for 3 days post sampling the number of fully emerged mosquitoes were counted. For the semi-field trial 5, 291.5 l barrels were placed at two locations in the district (n=10 barrels). Barrels were filled to 189 l with water and 1 kg rabbit pellets, lids were cut out to resemble open catch basin lids and a weep hole was cut to maintain water levels at no greater than 189 l. The 5 barrels received Sumilarv wsp, Tekko granules, Altosid XR, Altosid XR buried in a mixture of 5 gallons of clean soil/sand mixture, or untreated control. The sampling, container, and counting protocol as the catch basins was used for the barrels. In both the field and semi-field trials Altosid XR fared worse than Sumilarv or Tekko in controlling emergence of adult mosquitoes.