Investigation of the synergistic effect of two predatory mites, Phytoseiulus persimilis and Amblyseius swirskii (Acari: Phytoseiidae), in the biological control of Tetranychus urticae (Acari: Tetranychidae)

Tetranychus urticae (Acari: Tetranychidae) is a polyphagous pest that causes significant economic losses in multiple crop plants. Controlling T. urticae often involves intensive acaricide applications. The use of acaricides also significantly affects human health and ecosystem diversity due to residues and toxic effects in agricultural products. In this study, the efficacy of two predatory mites, Phytoseiulus persimilis and Amblyseius swirskii (Acari: Phytoseiidae), was determined against T. urticae when released as single species and when both species were released together on tomato plants under greenhouse conditions during autumn 2022. The study found that the highest T. urticae density per leaf, with 40.88 ± 0.79 individuals (eggs + motile) in the control group, was reached at the eighth week. In the same week, the highest impact on T. urticae, with 7.57 ± 0.42 individuals (eggs + motile), was observed in the treatment group where P. persimilis + A. swirskii were used together, compared to the untreated. According to the current results, the combined use of two predatory species (P. persimilis and A. swirskii) has been found to significantly suppress the population of T. urticae.