| Ginkgo biloba L.originated from ancient seed ferns during Permian times, and overgrown in Jurassic period. During the Tertiary and Quaternary periods great upheavals of the earth, followed later by an ice age,destroyed the ginkgo trees and other ginkgoales in most of the world. The destruction was least in China for its geographic superiority and climate condition.Therefor Ginkgo biloba tree was called as"a living fossil"and"a panda in the plant field".G. biloba L. is reputed for phytopharmaceuticals, specially has an effect on cerebrovascular, cardiovascular disease, senile dementia and so on and has been developped as pharmaceuticals, health products, cosmetics, beverages and the like. At the same time, G. biloba has the characteristic against pests and the studies on its resistance have been a focus due to phytopesticides environment-friendly and resistance-free. However, at present, there are much less pests studied, specially lacking on mites which are serious for agriculture. At the other hand, there are not the same viewpoint for the resistant components from G. biloba.This paper has systematacially studied the resistance of G. biloba against spider mites according to the general law for studying on phytopesticides. Main contents included that under the nonlimited condition, the selectivity of Tetranychus urticae Koch and Tetranychus viennensis Zacher to G. biloba leaves, and under limited one, the effects of G. biloba on the survival and fecundity of them.Volatile components of G. biloba leaves were identified with GC-MS after volatiles were collected with solid phase microextraction, and antifeedant activity of them were determinated with Y-tube olfactometer. The selective antifeedant activity of spider mites against G. biloba and the contact toxicity of G. biloba against spider mites were bioassayed with nine kinds of monomers in G. biloba at the first in the world. It was compared that the toxicity of extracts against T. viennensis that were extracted from foliar powder of G. biloba with three extraction processes: aqueous solution of powder with microwave treatment followed ethanol and ether extraction, organic solvents and alkaline solution extraction, ether extraction and adsorption with macroporous resin.The results showed that under the nonlimited condition, two kinds of spider mites had absolutely antifeeded on G. biloba leaves, and under the limited one, the survival time when spider mites were confined in G. biloba leaves reduced and the fecundity of spider mites were suppressed absolutely. Twelve kinds of volatile constituents from G. biloba leaves were identified, and they have a certain effect on the antifeedant activity of spider mites.At the same concentration, nine kinds of active constituents in G. biloba had more antifeedant activity on G. biloba than their contact toxicity against spider mites, and there was interspecific difference between two kinds of spider mites. The toxicity of ginkgolide A against T. viennensis had a prominent effect, the ginkgolic acids, which were generally thought as toxic substance, however, had not a prominent effect on the contact toxicity against spider mites.The effluent after absorption of macroporous resin had 93.25% of corrected mortality against T. viennensis, the eluate that was eluted by ethanol(80%), methanol:ethyl acetate(80:20 V/V) and NaOH (5%), respectively, had much less effect on the mortality of T. viennensis. It was eliminated from extraction processes of acaricides that the aqueous solution of foliar powder of G. biloba were treated with microwave, however, the corresponding extraction process of 70% ethanol and ether treatment had 91.38% of corrected mortality against T. viennensis. There was not an ideal toxicity from extracts of organic solvent and alkaline solution, aqueous solution of G. biloba had a certain toxicity.Rhus typhina L.(Anacardiaceae), Buck's horn or Staghorn, which originates from the eastern part of Northern America, is a 5～8 m high shrub or a small arbor, its unpaired serrated leaflets and fruits like torchs, turn bright red in autumn. It was introduced as an ornamental plant from USA by our country in 1959, and so far have been distributed over more twenty provinces and municipalities. R. typhina has been not only used as a plant of enhanced bank and circumscribed sand, but also has been a resistance against some pests. Unfortunately, it has been blamed for its overgrowth and exotic characteristics. Therefor, studies on its resistance against pests have been rare.Studies on R. typhina followed the methods as same as G. biloba. The results showed that under nonlimited condition, selective rate of two kinds of spider mites to staghorn leaves was less 10%, respectively, and under limited one, the survival time when spider mites were confined in the leaves of R. typhina reduced and fecundity was sppressed absolutely. Eleven volatiles from R. typhina leaves were identified as acids, alcohols, phenols and antifeedant activity of spider mites on them were demonstrated with Y-tube olfactometer. Ethyl acetate extract and the eluate which was eluted with petroleum ether:ethyl acetate(65:35 V/V) after adsorption of macroporous resin DM130 from leaves of R. typhina displayed acaricidal properties towards T. viennensis, respectively, and they were preliminarily identified as weak polar acids and phenols.
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