سازگاری کنه‌ی شکارگر Phytoseiulus persimilis (Acari: Phytoseiidae) با غلظت‌های زیرکشنده‌ی کنه‌کش بایفنازیت در شرایط آزمایشگاهی

The two-spotted spider mite, Tetranychus urticae Koch, is a polyphagous pest with wide host plants range which causes severe damage in different agro-ecosystems annually. High reliance on chemical pesticides in management programs of this pest has resulted undesirable effects on non-target organisms and therefore, search for alternative methods are urgently needed. Integrated control using natural enemies and chemical pesticides is among the management strategies of this pest and its potential in suppression of population of T. urticae could be considered. The predatory mite Phytoseiulus persimilis Athias-Henriot is one the most important natural enemies of T. urticae worldwide and its feeding activity on different life stages of this pest has considerable role in decreasing population density of T. urticae. In the present study, sublethal effects (LC10 = 21, LC20 = 52 and LC30 = 100 ppm) of Bifenazate (Floramite® 24% SC) on the biological parameters of this predatory mite (two subsequent generations) was evaluated under laboratory conditions with 25 ± 1 ºC, relative humidity of 65 ± 5 % and a light period of 16 hour. Data analysis was performed using Age-stage two sex life table theory. Sublethal concentrations have no obvious effects on oviposition period of treated females. Total fecundity of treated female was not significantly affected by different treatments tested (control = 103.93 ± 2.91, LC10 = 103.83 ± 2.21, LC20 = 102.98 ± 2.99 and LC30 = 100.27 ± 2.57 egg). Furthermore, results obtained in the present study revealed that sublethal concentrations of Bifenazate had no significant effects on biological parameters of offspring form treated females. Accordingly, duration of pre-adult development at control and sublethal concentrations of LC10, LC20 and LC30 was 5.04 ± 0.09, 5.14 ± 0.10, 5.30 ± 0.12 and 5.33 ± 0.15 day, respectively. The net reproductive rate (R0) of P. persimilis was not significantly affected and recorded value for this parameter at control and above-mentioned concentrations was calculated as 44.36 ± 2.86, 34.13 ± 3.15, 33.63 ± 2.96 and 33.49 ± 3.10 (offspring), respectively. In addition, sublethal concentrations had no negative effects on the intrinsic rate of increase of this predatory mite (control = 0.313 ± 0.012, LC10 = 0.307 ± 0.012, LC20 = 0.306 ± 0.010 and LC30 = 0.303 ± 0.011 day-1). Our findings revealed that sublethal concentrations of Bifenazate had no negative effects on biological parameters of P. persimilis and hence, in management program of T. urticae potential of simultaneous application of these two control procedures should be noticed.