Selection Of Tetranychus Viennensis Zacher And Tetranychus Urticae Koch To Different Plants

Effects of seven species of plants including M. pumila Mill, S. sibirica L., C. sinensis Koehne, M. azedarach L., G. biloba L., R. typhina Torner, E.japonica Thunb on the development and fecundity of T. viennensis Zacher and T. urticae Koch were studied by the leaf-dish rearing method. The physical structures of different plants were observed and the main components in different plants were determined. The olfactory respones of two spider mites to different plants odors with"Y"-olfactometer were observed. Volatiles from fresh leaves of different plants were extracted with SPME (solid phase microextraction) and composition and contents of volaties were determined with GC-MS (gas chromatograph-mass spectrometer). The major results were listed as follows:1 Effects of seven species of plants on the development and fecundity of T.viennensis Zacher and T.urticae KochEffects of different plants on the development and fecundity of T. viennensis and T. urticae were observed at 25℃in the photoperiod incubator. T. viennensis feeding on the leaves of M. pumila and S. sibirica had the fast rate of development, the high ability of reproduction, the long time survival of female adults. The mites feeding on the leaves of C. sinensis and E. japonica had the low rate of development, the low ability of reproduction. For the development periods and fecundity of T.viennensis Zacher, there were significant differences between the mites on the leaves of C. sinensis, E. japonica and on the leaves of M. pumila, S. sibirica. The mites feeding on the leaves of M. azedarach, G. biloba and R. typhina died at the periods of larvae, these three leaves produced the bad effect on the development of T. viennensis. T. urticae feeding on the leaves of M. pumila and S. sibirica had the fast rate of development, the high ability of reproduction, the long longevity of female adults. There were no significant difference between T. viennensis and T. urticae feeding on the leaves of M. pumila and S. sibirica. T. urticae feeding on the leaves of M. azedarach and R. typhina also could develop and oviposite naturally. T. urticae feeding on the leaves of C. sinensis, G. biloba, E. japonica had the low rate of development, the low ability of oviposition. Furthermore, T. urticae feeding on the leaves of G. biloba had the shortest developmental periods, the lowest fecundity and the shortest longevity. In a word, M. pumila and S. sibirica benefited for the two spider mites. C. sinensis, M. azedarach, G. biloba, R. typhina and E. japonica produced the disadvantagous effects on the two spider mites.2 The physical structures and chemical components of different plantsHairs of leaves of M. pumila, S. sibirica were soft and their epidermises were thin. These characteristics benefited for the development and fecundity of the two spider mites, and also benefited for the selection of the two spider mites to the leaves. There were no hairs on the leaves of Melia azedarach L., G. biloba and E. japonica. Epidermises were rigid and thick. The mites on these leaves died easily. These structures didn't benefit for the selection of the two spider mites.3 The chemical components of different plantsLeaves of M. pumila, S. sibirica, C. sinensis, M. azedarach, G. biloba, R. typhina, E. japonica had different contents of chemical components. Leaves of M. pumila, S. sibirica had the high content of nutriental substances. Leaves of M. pumila had the highest content of soluble sugar (19.92%), S. sibirica had the highest content of crude fat (9.70) and total nitrogen (4.00%). These two leaves benefited for the development and fecundity of T. viennensis and T. urticae. Leaves of G. biloba, R. typhina, E. japonica had the high content of secondary components-tannin. Leaves of G. biloba had the highest content of tannin (28.76%).These three leaves didn't benefit for the development and fecundity of the two spider mites, in whicn G. biloba had the worst effect on the two spider mites. Furthermore, ratio of nutriental substances to tannin in leaves of M. pumila was the highest (5.2:1), ratio of nutriental substaces to tannin in leaves of G. biloba was the lowest (0.35:1). The high ratio of nutriental substances benefited for the selection of the two spider mites to plants. The low ratio of nutriental substances made against the selection of the two spider mites to plants.4 The olfactory responses of T. viennensis and T. urticae to different plants odors:Olfaction takes part in the responses during the two spider mites settling down host plants, which means the mites are affected by odors from host plants. Different host plants had different effects on the olfactory responses of T.viennensis Zacher and T.urticae Koch. Some plants attracted strongly, some were less than the others. Other plants tested had neither attraction nor repulsion to the mite. M.pumila, as the host plants of the two spider mites, attracted strongly than other plants. Odors from leaves of R. typhina were repulsive to T. viennensis Zacher. Odors from leaves of C. sinensis and G. biloba were repulsive to T. urticae Koch.5 Composition and contents of volatiles from intact leaves of G. biloba and R. typhinaThere were 8 species of volatiles from leaves of G. biloba and the content of Benzo-1,5-diazabicyclo[3.2.2]nonene(16.39%) was the highest. There were 6 species of volatiles from leaves of R.typhina and the content of Benzo-1,5-diazabicyclo[3.2.2]nonene(23.44%) was the highest. It's preliminarily considered that this volatile was the mutual components from odors of G. biloba and R. typhina.