Thermal requirements and life table parameters of the predatory mite, Neoseiulus californicus (McGregor) fed on Tetranychus urticae Koch (Acari: Phytoseiidae: Tetranychidae)

Abstract

The predatory mite, Neoseiulus californicus (McGregor) (Acari: Phytoseiidae) is an important biological control agent of the two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae) infesting many crops worldwide. Biology, life table parameters and thermal requirements of N. californicus were evaluated in laboratory at 20, 27, 30±2oC and 70±5% RH. Spider mite, T. urticae is an important pest of soybean crop in Egypt. The duration of the immature stages of N. californicus ranged from 4.22 to 7.35 days for female and from 3.80 to 7.10 days for male when they were kept at 20 and 30°C, respectively. The mean generation time (TG) decreased with increasing temperature from 19.48 days to 12.93 days at 20 to 30°C, respectively. The intrinsic rate of increase (rm) and finite rate of increase (λ) were highest at 27 and 30 oC. The highest total consumption rate of prey was 223.4 individuals when adult female fed on T. urticae motile stages at 30 oC, while the lowest rate was 162.60 individuals at 20 oC during the whole life span. Minimum developmental thresholds (t0) of egg, larva, protonymph, deutonymph and total immature stages of N. californicus female averaged 13.20, 12.75, 3.29, 0.0 and 6.66 oC, respectively. The predatory female of N. californicus required 500 DDUs to reach adulthood. Therefore, a thermal range of 27oC was the most suitable condition to rear the target predatory mite.