The effects of milbemectin and spirodiclofen resistance on Phytoseiulus persimilis A.-H. (Acari:Phytoseiidae) life table parameters

Phytoseiulus persimilis A.-H. (Acari: Phytoseiidae) is one of the effective predatory mites used in the biological control of Tetranychus urticae Koch (Acari: Tetranychidae) in agricultural production areas. The objective of our study was to determine the effects of acaricide resistance on the life table parameters of P. persimilis. In the study, a 31-fold milbemectin-resistant population named P5 and an 108-fold spirodiclofen-resistant population named S5 were obtained as a result of selection from a susceptible laboratory population of P. persimilis. The leaf discspray tower method was used for the selection. Pre-oviposition, oviposition and post-oviposition periods, adult life span, total number of eggs laid per female, net reproductive rate (R-0), intrinsic rate of increase (r(m)) and mean generation time (T) parameters of P5, S5 and susceptible P. persimilis populations were compared and the life table created. In P5, S5 and susceptible populations, mean numbers of eggs per female were found to be 56.8, 41.6, 33.4, respectively, and to differ significantly (P < 0.05). The oviposition period and adult life span were found to be significantly longer in the P5 population (21.2 and 23.7 d) than the S5 population (15.8 and 18.3 d) and the susceptible population (14.9 and 17.8 d) (P < 0.05). In all three populations, the pre-oviposition period was found to be 1.0 day. The net reproductive rate (R-0) and intrinsic rate of increase (r(m)), which are the most important parameters of the life table, were statistically similar in the P5 (35.8 and 0.30) and S5 populations (23.9 and 0.26), and higher than the susceptible population (20.0 and 0.24), respectively (P < 0.05). These results indicated that the resistance of milbemectin and spirodiclofen in P. persimilis have positive effects on some life table parameters and these results may be useful in IPM programs.