| Polygonum orientate.L was investigated for its acarocidal activity against Myzus persicae (Sulzer), a serious pest of many crops including vegetables, fruit crops and flowers. P. orientale.L was extracted using four solvents: methyl alcohol, chloroform, petroleum ether and water. The crude extracts were used for bioassay to evaluate their acarocidal activities against M.persicae and electrical physiologyy-EAG analysis was carried out in the laboratory. At the same time, the crude extracts were separated and purified.The results indicated that methyl alcohol was the best solvent. Four kinds of extracts, when tasted as systemic and contact poison, had no significant effects on the activity of killing pests. In four different kinds extracts, extracts treated with methyl alcohol had significant activity repellent And the repellent rate raised accordingly with the increase of dosage.In four extracts from PMEW treated with methyl alcohol and water, petroleum ether, chloroform and ethyl acetate, extract rate of methyl alcohol and water was the highest. The extracts were bioasseyed to evaluate their acarocidal activities. The results showed the extract of ethyl acetate was the best.The silica gel column was used to separate and purify bioactive constitutes of the crude mixture extracted by ethyl acetate. A total of 12 bands were seen by TLC analysis only the band 5 appeared a strong acarocidal activity.Studies on Eletrpantennogram-EAG indicated that the EAG response of extract of methyl alcohol was the most intense. EAG response raised accordingly with the increase of dosage.
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