Toxicity of the acaricide bifenazate to the predatory mite Phytoseiulus persimilis(Acari: Phytoseiidae) and the feasibility of using bifenazate in conjunction with P. persimilis to control the two-spotted spider mite Tetranychus urticae(Acari: Tetranychida

[Objectives] To assess the toxicity of the acaricide bifenazate on the predatory mite Phytoseiulus persimilis(Acari: Phytoseiidae), and evaluate the feasibility of using this acaricide in conjunction with P. persimilis to control the two-spotted spider mite Tetranychus urticae(Acari: Tetranychidae). [Methods] The effect of bifenazate on the fecundity and mortality of adults and nymphs of P. persimilis, and the efficacy of a combination of P. persimilis and bifenazate in controlling T. urticae were tested in the laboratory. [Results] At a concentration of 143 mg/L, bifenazate had no effect on the mortality and fecundity of P. persimilis. Adult and nymph mortality were 2.30% and 2.04% respectively after 96 h. The treatment group had an average fecundity of 15.08 eggs per female, which was not significantly different to that of the control group(15.45 eggs per female). The average hatchability of the treatment group was 98.63%, which was also not significantly different to that of the control group(98.13%). A combination of bifenazate and P. persimilis resulted in fast and persistent control of T. urticae, with a control efficacy of 97.35% after 2 d and 100% after 18 d. [Conclusion] Bifenazate does not affect P. persimilis but is effective against T. urticae. The combined use of bifenazate and P. persimilis is effective in controlling T. urticae.