Abstract: The selectivity of Tetranychus urticae Koch and Tetranychus viennensis Zacher to the Buck's horn (Rhus typhina L.) and effects of R. typhina on the survival and fecundity of spider mites confined in the Buck's horn leaves were bioassayed in the laboratory. The results indicated that the selecting rates of T. urticae and T. viennensis for Rhus typhina L. were 9.5%, 6.5%, 5%, 5% and 2%, 5%, 1%, 0 at 2 h, 6 h, 10 h, 12 h, respectively. The survival of T. uiennensis confined on R. typhina leaves was fully inhibited after 144 h, and the fecundity was going down with increase of the survival time, and terminated at 96 h. The survival rate of T. urticae confined on R. typhina leaves was 0 after 240 h, and no oviposition was observed during the whole observation period from 24 h to 216 h. It was so concluded that R. typhina has the high antifeedant activity against spider mites and may distinctly inhibit the survival and fecundity of spider mites, but the inhibition is inter-specifically different for spider mites.

Key words: Spider mites, Rhus typhina, mite resisitance, bioassay