TY - JOUR JF - mdrsjrns JO - JAST VL - 20 IS - 3 PY - 2018 Y1 - 2018/5/01 TI - Effect of Different Predator: Prey Release Ratios of Phytoseiulus persimilis and Typhlodromus bagdasarjani (Acari: Phytoseiidae) on Reduction of Tetranychus urticae (Acari: Tetranychidae) on Cucumber under Microcosm Conditions TT - تأثیر نسبت‌های مختلف رهاسازی شکار: شکارگر در دو کنه شکارگر Phytoseiulus persimilis و Typhlodromus bagdasarjani بر کاهش جمعیت کنه تارتن Tetranychus urticae روی خیار در شرایط میکروکازم N2 - Prey suppression by predators depends on effective predator: prey release ratios. The effectiveness of Phytoseiulus persimilis Athias-Henriot and Typhlodromus bagdasarjani Wainstein and Arutunjan was evaluated at different predator: prey release ratios for suppression of Tetranychus urticae Koch populations on cucumber plants in the microcosm condition based on three experiments. In the first experiment, 7 days after T. urticae releases, the most reduction in the different stages (densities) of T. urticae and the most increase in both P. persimilis and T. bagdasarjani were observed in predator: prey release ratio of 1:4 followed by ratios of 1:10 and 1:20. In the second experiment, one day after T. urticae release at predator: prey release ratio of 1:4, there was no significant difference between predators effect on the decline of T. urticae stages (densities). In this case, more T. bagdasarjani at all stages was observed on the plants in comparison with P. persimilis. According to the third experiment, 7 days after T. urticae release, there was no significant difference between predator: prey ratio of 1:4 of P. persimilis and 1:2 of T. bagdasarjani on T. urticae suppression. In this case, more P. persimilis was observed on plants in comparison with T. bagdasarjani. Our study demonstrates that the most suppression of T. urticae populations occurred in predator: prey ratio of 1:4 for both predators. Based on our findings, we suggest that P. persimilis and T. bagdasarjani can be released at a ratio of 1:4 for successful control of T. urticae on cucumber. SP - 509 EP - 518 AU - Moghadasi, M. AU - Allahyari, H. AD - Department of Plant Protection, College of Agriculture and Natural Resources, University of Tehran, Karaj, Islamic Republic of Iran. KW - Biological control KW - Predatory mites KW - Spider mites. UR - http://jast.modares.ac.ir/article-23-19732-en.html ER -