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 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.

Tetranychus urticae Koch is a worldwide agricultural pest mite that feeds on more than 1100 kinds of crops. The mite has developed a high level of tolerance to high temperatures, but the physiological mechanism underlying the outstanding adaptability of this pest to high temperatures remains unclear. To clarify the physiological mechanisms of T. urticae in response to short-term heat stress, four temperatures (36, 39, 42, and 45 °C) and three short-term heat durations (2, 4, and 6 h) were conducted to test the effects on protein content, the activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), and the total antioxidant capacity (T-AOC). The results showed that protein content, antioxidant enzyme activity, and T-AOC in T. urticae were significantly induced by heat stress. These results suggest that heat stress induces oxidative stress and that antioxidant enzymes play an important role in reducing oxidative damage in T. urticae. The data of this study will provide a basis for further research on the molecular mechanisms of thermostability and ecological adaptability of T. urticae.

Tetranychus urticae Koch is a worldwide pest mite which can cause continuous damage to multiple plants even in hot environment such as greenhouse due to its strong endurance to high temperature. In order to clarify the physiological mechanisms of T. urticae in response to short-term heat stress, four high temperatures (36, 39, 42, and 45°C), three short-term heat durations (2, 4, and 6 h) were conducted to test the effects on the protein content of T. urticae and the activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) and total antioxidant capacity (T-AOC), respectively. The results showed that protein content, antioxidant enzymes activity, and T-AOC in T. urticae were significantly affected by both the high temperature and duration after treatment, meanwhile, they showed same trends of increased at 25–39℃, then decreased at 39–42℃ except for CAT activity. The highest values of SOD activity, POD activity and T-AOC were all obtained at 39℃-4h, and that of CAT activity was obtained at 39℃-2h. The higher levels of T-AOC serve an important signal demonstrating that T. urticae has other antioxidant mechanisms except for antioxidant enzymes. Those results suggested that heat stress induces oxidative stress, and antioxidant enzymes played important role in reducing oxidative damage in T. urticae. which provided a basis for further research on the molecular mechanisms of thermostability and ecological adaptability of T. urticae.