Abstract:

The selectivity of Tetranychus urticae and Tetranychus viennensis to Ginkgo biloba leaves was determined by means of method of petri dish, and elucidated the resistance of G.biloba against spider mites, and then the influence of volatiles from G.bioloba leaves on selection behavior of spider mites was explored.Volatiles from G.biloba leaves which were collected with solid phase micro extraction(SPME) and preliminarily identified by GC-MS are nonanoic acid, tetradecanoic acid, pentadecan oic acid, bexadecanoic acid, 2-pentadecanone, 6,10,14-trimethyl-,benzophenone, butylated hydroxytoluene, phenol,4,6-di(1,1-dimethylethyl)-2-methyl,2-buten-1-ol,3-methyl-,1,8-naphthyridin-2-amine,5,7-dimethyl-, 9H-pyrido[3,4-b]indol-7-ol,1-methyl- and 4-hexen-2-yn-1-one,1-phenyl-5-(1-piperi) and so on. The bioassay on selectivity of two kinds of spider mites to G.biloba leaves and apple leaves or clear air was carried out with Y-tube olfactometer. Results showed that the antifeedant rates of two kinds of spider mites against G.biloba leaves are all 100%. The selection rate of T.urticae and T.viennensis to G.biloba leaves in odour source group, G.biloba leaves vs. apple leaves, is 22.2% and 23.5%, respectively. It is 21.3% and 24.8% in G. biloba leaves vs. clear air, respectively. There is highly significant difference between treatments and controls, apple leaves or air. Two kinds of spider mites antifeedant against G. biloba leaves and volatiles from G. biloba leaves are an important factor that affects the selection of spider mites to hosts.

Key words: solid phase microextraction(SPME), gas chromatography-mass(GC-MS), Tetranychus urticae, Tetranychus viennensis, bioassay