بررسی مقایسه‌ای نرخ شکارگری کنه Neoseiulus californicus (Acari: Phytoseiidae) پرورش یافته در نسل‌های متمادی روی رژیم‌های غذایی متفاوت

The predation rate of mass-reared biological agents is essential in the selection and efficiency of appropriate combinations of beneficial species for biological control. Neoseiulus californicus (Acari: Phytoseiidae) is important predator that fed on plant injurious mite in greenhouses. In the present study, predation capacity of this mite in control of Tetranychus urticae as a serious pest in greenhouse were studied under laboratory conditions (27± 0.5 ̊C, 60% RH and photoperiod of 16:8 (L: D)). In order to investigate the rearing methods of the predatory mite, different diets including different biological stages of four storage mite species Tyrophagus putrescentiae, Tyrolichus casei, Rhizoglyphus robini and Blomia tropicalis with corn pollen were used in rearing containers on wet sponge. Storage mites fed on wheat bran, yeast and corn pollen. For study of the efficiency of the predatory mites reared in several generations (one, five, 10 and 15 generations), at least 10 predatory mites were isolated from the colonies. The predation rate of 2-3-day-old females from two-spotted spider mite eggs was counted separately within 24 hours. 20 eggs of the spider mites of the same age were used on bean leaves with dimensions of 2×2 cm2 and the number of eaten the eggs was compared. A completely random design with the repeated measure anova method was used. There was a significant difference in the predation rate of the predatory mites reared on these storage mite species. The average predation rate of mites in the four tested generations when fed on B. tropicalis and T. putrescentiae (10.50±0.26 and 8.22±0.39 respectively) was significantly higher than the predatory mites were fed two species T. casei and R. robini (3.78±0.37 and 5.68±0.35, respectively). The predation rate of N. californicus in several generations was significantly different from each other’s. The consumption number of the spider mite eggs has decreased in the long-term storage of the predatory mites. For example, the predation rate of the predatory mites reared on B. tropicalis in the first, fifth, tenth and twentieth generations was 13.22±0.95, 10.55±0.17, 9.33±0.37 and 88.8±1.03, respectively. The predation rate in the first, fifth and tenth generations has a significant difference with the predation rate of the 20th generation. Blomia tropicalis and T. putrescentiae are suitable for mass rearing of N. californicus for up to 10 generations along with corn pollen. For long-term rearing, different biological stages of the two-spotted spider mite should be added to the rearing environment in order to have the necessary efficiency as a biological control agent.