Effects of B-azolemiteacrylic on life-history traits and demographic parameters of two-spotted spider mite, Tetranychus urticae (Acari: Tetranychidae)

Abstract

AbstractThe present study was conducted to evaluate sublethal effects of B-azolemiteacrylic on the two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae). Female adults of T. urticae were exposed to LC10 and LC30 of the acaricide, and the effects on treated females and their offspring were evaluated. The results showed that the fecundity of F0 female adults treated with LC10 and LC30 of B-azolemiteacrylic was reduced by 30.9 and 39.2%, respectively. Longevity and oviposition period of the females were significantly reduced as well. The developmental duration of egg and deutonymph stage of the F1 generation were not significantly different from that of the control. The protonymph stage after LC30 treatment lasted significantly longer, whereas the larva, deutonymph and female stage were significantly shorter than the control. The oviposition period of the F1 generation was significantly shortened, the fecundity of each female decreased significantly, and the ratio of female-to-male was reduced too. Moreover, the average generation period of T. urticae after LC10 and LC30 treatments was shorter than that of the control, and the net production rate (R0), intrinsic rate of increase (rm) and finite rate of increase (λ) were all reduced by 33.3, 7.5 and 1.9% (LC10 treatment) and by 51.3, 14.8 and 3.6% (LC30 treatment), respectively. The population doubling time was prolonged by 7.5 and 14.8% after LC10 and LC30 treatments, respectively, compared with the control. These results indicate that B-azolemiteacrylic may effectively inhibit the development rate of the F0 and F1 populations of T. urticae, which will help design integrated strategies for the comprehensive control of T. urticae and rational use of pesticides in the field.