Studies On The Fugicidal Activity And Formulation Processing Of Taraxacum Mongolicum. And Solanum Nigrum L.

The studies include the extracting solvent and method, manufacture of E.G. and antifungal activity of Solarium nigrum L. and Taraxacum mongolicum.The results are as follow.1. Two kinds of extracting methods and three kinds of solvents were applied to extract the dry powder of Solarium nigrum and Taraxacum mongolicum.The effects of the antifungal anctivity in the extracts were valuded by mycelium growth rate test.It showed that the extracting methods was unimportent and ancohol was the best sovent to extract the dry powder.2. The best solvents was xylene and N,N-dimethylformamide that dissolved the extract perfectly. After the test of emulsion stability and diflusivity ,it was the ingredients of S. nigrum emulsifiable concentrates(E.C) that extract 20%,emulsifers 15%, N,N-dimethylformamide 5%,xylene 60%;The ingredients of Taraxacum mongolicum emulsifiable concentrates(E.C) were extract 15%,emulsifers 20%, N,N-dimethylformamide 5%,xylene 60%3. The S. nigrum and T. mongolicum E.G. could inhibit apparently the growth the mycelium of five pathogens,at the dosage of 2000ppm. While the pathogens were dealt after nine days ,the two fungicides still had a certain effect.lt was 1262ppm and 997ppm that the ECso of S. nigrum E.G. to Rhizoctonia solani and Fucarium oxysporun respectively;and the ECso of T. mongolicum E.G. was 1629 ppm and 1655 ppm respectively to the fungi.4. Foliar application of S. nigrum E.G. and T mongolicum E.G. to detached cucumber and potato leaves could effectively reduce the disease severity of their powdery mildew.Their therapeutic efficacy was 73.17% and 64.95% to the cucumber powdery mildew respectively,but the protective effecacy was little.The therapeutic efficacy of the S. nigrum E.G. to potato powdery mildew was about 60% that was almost as effective as that of the fungicide carbendazim(65.05%).However,the efficacy of T. mongolicum E.G. was decided by that of emulsifers.5. The results of the pot test showed that the therapeutic efficacy of the S. nigrum E.G. was 63.88% against the potato powdery mildew,almost as effective as that of carbendazim(70.28%) under the same condition of bioassay;the control effect to wheat powdery mildew was 36.38%.Z mongolicum E.G. had no effect on the two kinds of disease.6. By the phytotoxicity test, S. nigrum E.G. made the cucumber leaves disorder lightly at 20000ppm.Over the 10000pp,two kinds of the E.G. had no phytotoxicity reaction on cucumber and potato plant.7. Using thin layer chromatography(TLC) for detecting the alkaloid in the extract demonstrated that the kinds of alkaloid changed with the extract solvent.The solasonine and solamargine in the S. nigrum were found.There was another uncertained spot that the Rf value was 0.03.The Rf value of three alkaloid in T. mongolicum were 0.03,0.18 and 0.72.8. TLC bioassay results showed that the solasonine inhibitetd Alternaria solani and the solamargine had no efficay on the fungi;there was an abviously inhibiting A. solani and Cladoaporium cucumerinum spot of two kinds of the E.G. near the top line of the layerAbove studies will lay the foundation for research , exploitation and application of plant fungicide from Solanum nigrum and Taraxacum mongolicum.