Effect Of Several Plants And Extracts On Behavior Of Tetranychus Urticae Koch And Tetranychus Viennensis Zacher

The two-spotted spider mite(Tetranychus urticae Koch) and the hawthorn spider mite (Tetranychus viennensis Zacher) are two of the most important pest mites of apple trees in China. The selectivity of Tetranychus urticae Koch among in Malus pumila Mill., Mentha haplocalyx Briq., Allium sativum Linn., Euonymus japonicas Thunb., Ligustrum lucidum Ait., Solanum tuberosum L., Toona sinensis Roem., and Arachis hypogaea Linn, was determined by choice and no-choice laboratory bioassays. We also observed the development of T. urticae Koch on the leaf of S. tuberosum, comparing with A. hypogaea. The contact toxicity and repellent effects of the garlic straw extracts against on female adults of T. urticae Koch and T. viennensis Zacher were studied in the laboratory. The main results as follows:(1) M. pumila showed significant attraction than other plants but for S. tuberosum in choice tests. There was no significant difference between the selectivity of T. urticae Koch in A. hypogaea and S. tuberosum in choice test. There was no significant difference between the selectivity of T. urticae Koch in M. pumila (96.67%) and S. tuberosum (93.33%), which were significantly higher than other plants, at24h after treatment in no-choice tests. On the contrary, the selectivity in A. sativum (37.5%) was lowest, followed by L. lucidum and E. japonicas, which were40%and45%, respectively. The oviposition number per female T. urticae Koch reared on A. hypogaea was significantly more than S. tuberosum. There was no significant difference between the hatching rate of T. urticae Koch eggs in A. hypogaea and S. tuberosum. The mortality of young mites reared on S. tuberosum was significantly higher than A. hypogaea, which were84%and0,respectively.(2) The contact toxicity and repellent effects of the garlic straw extracts (with concentrations at20g/L, lOg/L,5g/L,2.5g/L and1.25g/L) against on female adults of T. urticae Koch and T. viennensis Zacher were studied in the laboratory. The results showed that the extracts at20g/L concentration caused the76.47%and54.88%corrected mortality48hours after treatment on T. urticae Koch and T. viennensis Zacher, respectively. The toxicity regression equation for extracts on T. urticae Koch and T. viennensis Zach48hours after treatment was y=1.278x+3.907and y=0.82x+4.065, and LC50value was7.1552g/L and13.77g/L, respectively. Repellency for T. urticae Koch was95.56%and65.22%after24h with the extract concentrations of lOg/L and20g/L, respectively. Other tested concentrations of extracts had no significant repellent effects. Each concentration of extract has significant repellent effect on T. viennensis Zacher and the repellent rates were higher than90%. The straw of garlic may have potential to be used in the sustainable management on T. urticae and T. viennensis.