کنترل زیستی Tetranychus urticae با رهاسازی جداگانه و ترکیبی کنه شکارگر Phytoseiulus persimilis با Neoseiulus cucumeris یا Amblyseius swirskii در تراکم‌های مختلف رهاسازی روی گیاه رز

The two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae) is a key pest of many greenhouse crops, including roses. The control of this important pest has been mainly based on the use of acaricides. Phytoseiid mites are used mostly for biological control of pest mites. In this study, control of T. urticae by single and combined release of Phytoseiulus persimilis Athias-Henriot with Neoseiulus cucumeris (Oudemans) or Amblyseius swirskii Athias-Henriot was evaluated at three release densities of 20, 40 and 100 predators per m2 in microcosm experiments (25±5 °C, temperature; natural light cycle of~14:10 h [L:D], photoperiod; 60±10%, RH).Sixteen rose plants at different stages of flowering were used per treatment, enclosed in a wood-framed cube cage (100×100×70 cm) covered with transparent plastic, with 20×30 cm openings on the lateral sides, covered with 200×200 µm fabric mesh. The final prey and predator populations were counted on 40 randomly selected leaves for each replicate. In all treatments, the release of predator(s) significantly decreased T. urticae population (approximately 30-40 mites per leaf) compared to the control treatment.The combined and single release of P. persimilis with A. swirskii or N. cucumeris had no significant difference in suppression of T. urticae at 5 and 30 days after releasing the predator, while combined releases decreased T. urticae population more than single release at 10, 15, 20, and 25 days after releasing the predator. Release densities of 20, 40, and 100 predators per m2 eradicated 97.65, 100, and 100 percent of the T. urticae population at 30 days after releasing the predator. Based on the results, a single release of 20 adults of P. persimilis per m2 would be sufficient to control T. urticae on rose plants, and long-term additional studies are needed in a rose greenhouse.