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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Eotetranychus hirsti Pritchard & Baker (Tetranychidae) is one of the important pests of fig trees that is widely distributed in fig orchards of Iran. The predatory mite Phytoseius plumifer Canestrini & Fanzago is a phytoseiid mite on fig that can feed and reproduce on E. hirsti. The effect of four constant temperatures (20, 25, 30 and 35°C) on demographic parameters of P. plumifer fed on nymphal stages of E. hirstiwas determined under laboratory conditions at 50 ± 5% RH and a photoperiod of 16:8 h (L: D). The total developmental time of immature stages of this predator decreased with increasing temperature from 20°C to 35°C, and varied from 17.13±0.23 to 6.55±0.19 days for females. The lower temperature threshold (Tmin) and thermal constant (K) for the total immature stages of this predator was estimated 10.33˚C and 166.67 degree-days by the ordinary linear model, 11.17˚C and 147.87 degree-days by the Ikemoto linear model, respectively. Female longevity was 67.79, 47.00, 35.11, and 27.42 days at 20, 25, 30 and 35°C, respectively. The highest values of total fecundity and daily fecundity were obtained at 25˚C (35.71±1.73 eggs) and 30˚C (1.57±0.02 eggs), respectively. The value of the intrinsic rate of increase (rm) increased as increasing temperature from 20°C (0.064±0.0012 day−1) to 30°C (0.180±0.0023 day−1), and then decreased at 35°C (0.153±0.0037 day−1). The highest and lowest values of the mean generation time (T) were 32.75±0.95 and 14.18±0.51 days, which were obtained at 20°C and 35°C, respectively. The results of this study revealed that of P. plumifer is effective predator of the fig spider mite and develops effectively at a broad range of temperatures.

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Eotetranychus frosti and Cenopalpus irani Dosse are pests of apple trees that are widely distributed in apple orchards in Iran. The functional responses and predation rates of Amblyseius swirskii, one of the most commonly utilized phytoseiid mites for biological control, on these two pests were evaluated at 25 ± 1 °C, with 16:8 h L: D, and a relative humidity of 60 ± 10 % on apple leaves. The results of predation rate experiments on the two prey species indicated that the predator consumed significantly more eggs than larvae and protonymphs whereas consumption of deutonymphs were very rare. Likewise, the results of logistic regression analysis showed that A. swirskii exhibited a Type II functional response on all immature stages of E. frosti and C. irani. Handling time (Th) increased as prey size enlarged; the lowest handling times were determined as 0.4858 and 0.3819 h on eggs of E. frosti and C. irani, respectively, whereas the highest were found to be 1.4007 and 1.0190 h on deutonymphs, respectively. Amblyseius swirskii had the higher attack rate coefficient (α) on immature stages of C. irani than E. frosti. Attack rate coefficients (α) varied significantly between life stages of both pests with the highest attack rate obtained on eggs, followed by larvae, protonymphs, and deutonymphs. Results of this study suggest that A. swirskii could be a highly efficient biological control agent of E. frosti and C. irani at least at low prey densities.

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