Comparative study on the control effectiveness of chemical agents against red imported fire ants in different habitats

The investigation of chemical control measures against Solenopsis invicta across diverse habitats was pivotal for developing targeted ant management strategies. Initially, thirteen baits were selected for laboratory efficacy trials targeting the red imported fire ant, with their insecticidal activity assessed based on mortality rates. Subsequently, field control trials were conducted to compare the efficacy of six selected insecticides across three distinct habitats: woodland, grassland and farmland. Laboratory experiments demonstrated that baits formulated with Meiyiwei (0.45% Tetramethrin+0.05% Cypermethrin), Youkewei (0.05% indoxacarb), Shujue (0.1% indoxacarb), Chuxing (0.1% indoxacarb), Dahao (0.1% indoxacarb), and Zhaoshifu (0.1% Dinotefuran) exhibited significant control efficacy against S. invicta, with corrected mortality rates of worker ants exceeding 90% on the 7^th day post-treatment. Field trial results demonstrated that all six tested insecticides achieved the highest comprehensive control efficacy in grassland habitats with low habitat complexity, whereas the lowest efficacy was observed in woodland with complex ecological environments. This study further revealed substantial variations in insecticidal efficacy among formulations from different manufacturers, even when active ingredients and their concentrations were nearly identical. These findings provide critical guidance for developing targeted control strategies against the red imported fire ant.