| The test studied the extraction rate of the ethanol extract from the root bark of T. wilfordii, the content of triptolide, total alkaloid in Tripterygium wilfordii Hook.f. and The toxicity determination of T. wilfordii emulsifiable concentrate(EC), T. wilfordii micro emulsion(ME), total alkaloid emulsifiable concentrate.The ethanol extract was extracted by percolation method and the average extraction rate was 2.43 g?15 g. The content of triptolide in the extract was determined by HPLC and the result is 12.62μg/g.According to the physico-chemical and bioactive properties of the extract, 5% T. wilfordii extract emulsifiable concentrate (EC) has been developed by choosing proper solvent and emulsifier. The results showed that the physico-chemical properties of the EC conform with the nationnal standards. The conponents of the EC are the extract of T. wilfordii (5%), solvent(55%), emulsifier(40%). The results of the tests on insecticiidal activities show that the EC has a better toxicity. The medium lethal concentration (LC50) against 2nd instar P. xylosella larvae, Myzus persicae are 32.30 mg﹒L-1, 334.87 mg﹒L-1. But the effect of the EC on Bemisia tabaci is not obvious, the medium lethal concentration (LC50) against Bemisia tabaci is 625.26 mg﹒L-1.3%T. wilfordii extract micro emulsion (ME) has been developed by using the extract as raw material. The test results showed that each physical-chemical index of the ME came up to national standards. The conponents of the ME are the extract from T. wilfordii (3%), solvent(30%), emulsifier(30%) and distilled water(37%). The results of the tests on insecticiidal activities showed that 3%T. wilfordii ME has worse toxicity than 5% T. wilfordii EC.Total alkaloid emulsifiable concentrate(EC) has been developed and the results of toxicity determination showed that total alkaloid EC has a strong toxicity. The medium lethal concentration (LC50) against 2nd instar P. xylosella larvae, Myzus persicae, Bemisia tabaci are 16.17 mg﹒L-1, 0.93 mg﹒L-1 and 6.42 mg﹒L-1.
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