author(s)
Faezeh Nojumian, Qodratollah Sabahi, Reza Talaei-Hassanloui, Ali Darvishzadeh

abstract
Effects of spirodiclofen as a tetronic acid pesticide were studied on demographical characteristics of Orius niger, a voracious predator of Tetranychus urticae. Developmental time of the first, third and fourth nymphal stages of the predator was significantly influenced by the acaricide treatment, however, the total developmental time of pre-adult stages was not influenced significantly. There were also significant differences in adult preoviposition periods. The intrinsic rate of increase (r) was 0.0949 d-1 in spirodiclofen treatment, which is significantly lower than control with 0.1184 d-1. Finite rates of population increase (λ) in control and treatment were 1.1257d-1 and 1.0995d-1, respectively. Mean generation time (T) also varied between control (31.33 d) and treatment (34.30 d), significantly. Gross reproductive rate (GRR) and net reproductive rate (R0) were not different after treatment, significantly. Although, spirodiclofen treatment revealed the species ability to survive, grow, develop, and reproduce successfully after the use of recommended doses.