The susceptibility of Reticulitermes chinensis (isoptera: Rhinotermitidae) to sulfluramid, imidacloprid and ivermectin

Reticulitermes chinensis Synder is one of the important termite species and is broadly distributed in China. Sulfluramid, imidacloprid and ivermectin are three important chemicals for termite control. To explore the feasibility of sulfluramid, imidacloprid and ivermectin for the control of R. chinensis, the toxicities and repellencies of these three chemicals to the workers of R. chinensis were evaluated in this study. The results indicated that the toxicity of ivermectin against the workers of R. chinensis was higher than that of sulfluramid and imidacloprid. At the 50 mg/L and 25 mg/L concentrations, the mortality of workers tested reached 100% at 2 days and 4 days after exposure to the treated-filter paper, respectively. The workers exposed to the filter paper treated with 500 mg/L or 250 mg/L sulfluramid solution died entirely at 3 days and 5 days after treatment, respectively, but the workers exposed to the same concentrations of imidacloprid solution did not die completely until the fifth day after treatment. Results also showed that the workers of R. chinensis exhibited different responses to the filter paper treated by sulfluramid, or imidacloprid and ivermectin. The number of workers that occurred in the treated-tube was significantly lower than the number that occurred in the untreated-tube when the filter paper used as the food of workers was treated by >250 mg/L of imidacloprid or 500 mg/L of sulfluramid. In addition, the 50 mg/L ivermectin and 500 mg/L imidacloprid exhibited significant anti-feeding activity on the workers of R. chinensis compared to the control. These results suggested that the suitable concentrations of all three chemicals tested have potential as the active component of baits for the control of R. chinensis.