Abstract:

To investigate the efficacy of different insecticides against workers of the red imported fire ant, (Solenopsis invicta), and to screen for safe, highly effective agents, to provide a reference basis for choosing agents to efficiently deal with the red fire ant infestation, the insecticidal activities of 23 commercial formulations were evaluated under indoor conditions (15-25℃) using the residual film and immersion methods. The results showed that spinetoram achieved 91% corrected mortality at 3 h post-treatment. At 24 h post-treatment, six insecticides, including dinotefuran and chlorfenapyr, caused 100% corrected mortality, while thiamethoxam, nitenpyram, and indoxacarb resulted in >95% corrected mortality. At 72 h post-treatment, three insecticides, including flonicamid, exhibited >93% corrected mortality. For the biological insecticides, Mamestra brassicae nucleopolyhedrovirus (MbNPV) achieved 100% corrected mortality at 48 h post-treatment, whereas Spodoptera litura nucleopolyhedrovirus (SpltNPV) and a matrine-azadirachtin mixture resulted in 97.78% and 80% corrected mortality at 96 h post-treatment, respectively. Consequently, it is recommended that six chemical insecticides such as dinotefuran and two antibiotic-derived insecticides including spinosad and spinetoram can be used in rotation with indoxacarb in field applications. The matrine-azadirachtin mixture is suitable for application in environmentally sensitive areas, such as water source protection zones, and the two nucleopolyhedrovirus formulations may be considered for trial use in such special habitats.

Key words: workers of the red imported fire ant, chemical insecticides, antibiotic insecticides, biology insecticides, commercial formulations, indoor rapid extermination