The Bioassay Of Crude Extracts From Ginkgo Biloba L. Leaves On The Contact Activity Against Tetranychus Viennensis Zacher

Ginkgo biloba L.originated from Permian times, and overgrown in Jurassic period. During the Tertiary and Quaternary periods great upheavals of the earth, followed later by an ice age, it was destroyed in most of the world except China for its geographic superiority and climate condition.Therefor it was called as"a living fossil"and"a panda in the plant field".G. biloba is reputed for effects on cerebrovascular, cardiovascular disease, senile dementia and so on and has the characteristic against pests. To explore it servicing for phytopesticides environment-friendly, this paper used various mehtods to extract the crude components from G. biloba leaves, and respectively bioassayed them on the contact toxicity against Tetranychus viennensis Zacher. The results showed the corrected mortality of extracts from non- microwave treated foliar powder of G. biloba by ethanol and ethylether was 68.97% and 91.38% respectively, it was better than extracts from microwave treated one. There was not an ideal toxicity from extracts of organic solvent and alkaline solution, aqueous solution of G. biloba had a certain toxicity.The effluent after the ether extraction and absorption of macroporous resin DM130 had 93.25% of the corrected mortality against T. viennensis. Hownever the eluates that were eluted by ethanol (80%), methanol : ethyl acetate (80:20 V/V) and NaOH (5%) had much less effect on the mortality of T. viennensis.