| Panoychus citri(McGregor) was a common and serious acarid in China. Chemical control was principal measure against this pest. The studies of botanical pesticides have important theoretical and practical significances. The effect of deterrent and toxicity from 20 species plants against P. citri was studied. The results are as follows:1 .The extractive rate of 20 species plants with ethyl alcohol was studied, and the effect of deterrent and toxicity from 20 species plants was tested. The extractive rate of Duchesncea indicaAndr.)Focke was 50.27%,the highest. The extractive rate of Iris tecorum Maxim and Paris polyphylla Smith was 20.23% and 19.80% .respectively. The results of the experiments also showed that the extracts of many common plants have noticeable effect of deterrent against P. citri. The deterrents rates of the extracts from /. tecorum and Croton tiglium L. against P. citri were 87.96% and 94.54% after 24h Respectively. The adjust mortality ratio of the extract of P. polyphylla Smith against P. citri was 75.79% after 48h. The extracts of these plants could be used to construct the plant protectant to control P. citri.2.Two kinds of examination methods ,soaking slides and blades, were used to make examination of toxicity. The adjust mortality ratio was 67.79% and 81.25% respectively.3.The extractive rate of 5 kinds of plants with ethyl alcohol ,chloroform and ethyl acetate was studied,and their bioactivity was tested. The results showed that the extractive rate in ethyl alcohol was the highest. The extractive rates of P. polyphylla, Solatium anquivi Lam.,Kanunculus japonicus Thunb and Anemone vitifolia Buch.-Ham. were all above 15%. The extractive rate of chloroform and ethyl acetate were almost under 6% ,and only the extractive rate of Solanum anquivi Lam. with ethyl acetate was 11.79%. So ethyl alcohol was the better solvent. The extract of P. polyphylla Smith with ethyl alcohol,chloroform and ethyl acetate (5000ug.ml-1) had high adjust mortality ratio,86.21%,98.28% and 86.21% respectively, and their LC50 was 1588.537ug.ml-1,1480.071 ug.ml-1 and 1402.954ug.ml-1. The extracts of K. japonicus with chloroform and A. vitifolia with ethyl acetate had high adjust mortality ratio,94.83% and98.28% respectively. The extracts of Girardinia palmate(Forssk.) with chloroform and ethyl acetate had high adjust mortality ratio, above 80%.4.Colum chromatography and thin layer chromatography were applied to purify the extract of P. polyphylla. And the toxicity of all cluates to P. citri were tested. 22 kinds of eluates were attained,of them the 1st was the eluate of petroleum ester and ethyl alcohol,and 2~8 were the eluates of ethyl alcohol, and 9~22 were eluates of ethylalcohol and methanol. By thin layer chromatography, 22 kinds of eluates were combined to 14 kinds of eluates, 2~3, 4-5, 6-7, 9-10, 11 - 12, 16-17 and 18-20 were allcombined eluates. Most eluates had high bioactivity to P. citri . The eluates of 11 -12,14 and 16-20 had high toxicity to P. citri, which their motality ratio reached at 100%.5.The synergism of 3 chemical materials to extract of P. polyphylla were studied. The synergism of pyrocatechol was noticeable. Their multiple of synergism of extract of P, polyphylla with ethyl alcohol, chloroform and ethyl acetate was 5.6,2.5 and 1.6 respectively. Calcium sulfate had high synergism to P. polyphylla with chloroform and ethyl acetate. Their multiple of synergism was 2.1 and 1.4. HP-1 had high high synergismto P. polyphylla with ethyl zlcohol. Its multiple of synergism was 2.1.6.The deterrent of extract of I. tecorum to P. citri and toxicity of combination of extract of P. polyphylla and phrocatechol were studied in the field. The result showed that the extract of /. tecorum to P. citri had high deterrent, quick effective and persistence, which its deterrent was 82.99%, 77.00%, 60.53% and 52.94% after 1, 3, 10, 15 and 20d,respectively. The combination of extract of P. polyphylla with ethyl alcohol and pyrocatechol to P. citri had high toxicity, quick effective and persistence, which its...
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