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

The 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 LC(10) and LC(30) of the acaricide, and the effects on treated females and their offspring were evaluated. The results showed that the fecundity of F(0) female adults treated with LC(10) and LC(30) 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 F(1) generation were not significantly different from that of the control. The protonymph stage after LC(30) treatment lasted significantly longer, whereas the larva, deutonymph and female stage were significantly shorter than the control. The oviposition period of the F(1) 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 LC(10) and LC(30) treatments was shorter than that of the control, and the net production rate (R(0)), intrinsic rate of increase (r(m)) and finite rate of increase (λ) were all reduced by 33.3, 7.5 and 1.9% (LC(10) treatment) and by 51.3, 14.8 and 3.6% (LC(30) treatment), respectively. The population doubling time was prolonged by 7.5 and 14.8% after LC(10) and LC(30) treatments, respectively, compared with the control. These results indicate that B-azolemiteacrylic may effectively inhibit the development rate of the F(0) and F(1) 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.