The effect of seven constant temperatures of 15, 20, 25, 27, 30, 35 and 37°C on developmental time of Neoseiulus barkeri Hughes were determined in laboratory conditions under 65%± 5% RH and a photoperiod of 12 : 12 (L : D) h on nymphal stages of Tetranychus urticae Koch. Total developmental time of females (from egg to adult emergence) at the above‐mentioned temperatures was 26.59, 14.43, 6.32, 5.64, 4.59, 3.98 and 4.67 days, respectively. Developmental rate of the N. barkeri increased as temperature increased from 15 to 35°C, but declined at 37°C. A linear and two nonlinear models were fitted to developmental rate of immature stages of N. barkeri to predict the developmental rate as a function of temperature, as well as to estimate the thermal constant (K) and critical temperatures (i.e., Tmin, Topt and Tmax). The estimated values of the Tmin and K for total developmental time using the linear model were 12.07°C and 86.20 degree‐days (DD), respectively. The Tmin and Tmax estimated by the Sharpe‐Schoolfield‐Ikemoto (SSI) model were 11.90°C and 37.41°C, respectively. The estimated Topt for overall immature stage development of N. barkeri by the Lactin and SSI models were 33.89°C and 24.51°C, respectively. Based on the biological criteria of model evaluation, the linear and SSI models were found to be the best models for describing the developmental rate of overall immature stages of N. barkeri and estimating the temperature thresholds.

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The life history and predation rate of Amblyseius swirskii Athias-Henriot feeding on Eotetranychus frosti (McGregor) (Tetranychidae) or Cenopalpus irani Dosse (Tenuipalpidae) were determined at 25±1°C, with 16:8 h L: D, at an average daily relative air humidity of 60±10% on apple leaves. A. swirskii successfully completed development, oviposition, and survival on both diets. Individuals of predator reared on E. frosti prey showed improved performance as compared to C. irani prey. The results indicated that its average duration of all immature stages on E. frosti and C. irani were 6.94 and 7.48 days, respectively. The adult female longevities were 39.81 and 32.41 days on the E. frosti and C. irani diets, respectively; also females laid a total of 34.69 and 25.96 eggs on the two different prey species, respectively. The intrinsic rates of increase (r) and net reproductive rate (R0) on E. frosti and C. irani were 0.179 and 0.140 day−1 and 18.50 and 11.68 female offspring, respectively. The transformation rate (Qp), stable predation rate (ψ), and finite predation rate (ω) of A. swirskii were higher on C. irani than when fed on E. frosti diet due to their higher predation rate. The transformation rate (Qp) of the predatory mite was 20.20 and 32.28 prey on E. frosti and C. irani, respectively. The net predation rate (C0) was not significantly different for A. swirskii on the two diets. The results of this study suggested that A. swirskii can successfully complete its life cycle on both preys and have excellent performance as biological control agent against both pest species.

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