Study On The Fungicidal Ingredient Of Mikania Micrantha H.B.K.

The previous research discovered that Mikania micrantha H.B.K. has strong growth inhibition to Glomerella cingulata Schr. et Spauld and other seven plant pathogens in vitro. It also showed good protective effect to Erysiphe graminis (DC.) Speer in vivo. In order to find fungicidal compounds from Mikania micrantha H.B.K and discuss its exploitation, the further research carried out according to the guidance of bioassaying. The results were as following:1. The whole of Mikania micrantha H.B.K. 8.0Kg were extracted with ethanol and got the ethanol extract 887.04g after evaporating the solvent in low pressure, the extract rate is 11.1%. The ethanol extract was suspended in distilled water and was successively extracted with petroleum ether, chloroform, ethyl acetate and n-butanol, after concentrating we got petroleum extract 170.52g, chloroform extract 19.90g, acetic ether extract 12.40g, n-butanol extract 37.88 and water residue 646.34g, respectively.2. The fungicidal activity of extracts from Mikania micrantha H.B.K. was tested in vitro and in vivo. The results showed that the petroleum and chloroform extract had strong growth inhibition to mycelia. The petroleum extract had good efficacy to Erysiphe graminis (DC.) Speer and Pseudoperonospora cubensis Berk et M.A.(curtis) Rostovzev. The chloroform extract had good therapeutic effect to Erysiphe graminis (DC.) Speer in vivo. What's more, the ethyl acetate extract and n-butanol extract also had good efficacy to Erysiphe graminis (DC.) Speer in vivo. At the concentration of 0.9g·mL^-1, the petroleum extract had strong inhibition to Rhizoctonia cerealis Vander Hoeven and Sclerotinia sclerotiorum (Lib.) de Bary in vitro, the inhibition rates were 100.0% and 56.4% respectively, and the chloroform extract had strong inhibition against all the tested fungi, especially to Rhizoctonia cerealis Vander Hoeven, Phytophthora capsici Leon, Macrophoma kuwatsukai and Exserohilum turcicum (Pass)Leonard. When the concentration was set at 0.18g·mL^-1, the petroleum extract had strong protective effect (56.3%) and therapeutic effect (45.1%) to Pseudoperonospora cubensis Berk et M.A.(curtis) Rostovze, which also had good protective effect (50.2%) and therapeutic effect (56.8%) to Erysiphe graminis (DC.)Speer in vivo. The chloroform extract had good therapy effect to Erysiphe...