Study on the Antifungal Activities of Mikania micrantha Extracts

The stems and leaves of Mikania micrantha were successively extracted with petroleum ether, ethyl acetate and ethanol. In vitro and in vivo test method was adopted to deten＇nine the inhibition activity of three solvent extracts against three plant pathogens. Growth rate method showed that ethyl acetate extract could significantly inhibit the mycelial growth of Botrytis circrea, Gtomerclla ciugulata and Fusarium bulbigeuum under the given concentration of 0.09 g/ml in dry sam- ple, and the inhibition rates were all greater than 90%. Organization test showed that the curative effect of petroleum ether extract against B. cirerea was 63.55% under the given concentration of 0.18 g/ml in dry sample, and the curative effect of ethanol extract was 71.47%. In the potting test against Erysiphe gramiuis, the curative effect of petroleum ether extract was 81.26%, while the curative effect of ethyl acetate extract was 62.07%.

Essential Oil from Inula britannica Extraction with SF-CO_2 and Its Antifungal Activity

The aim of this study was to determine the extraction technique of supercritical fluid carbon dioxide（SF-CO 2） for the essential oil from Inula britannica flowers and its antifungal activities against plant pathogenic fungi for its potential application as botanical fungicide.The effects of factors,including extraction temperature,extraction pressure,SF-CO 2 flow rate,flower powder size,and time on the essential oil yield were studied using the single factor experiment.An orthogonal experiment was conducted to determine the best operating conditions for the maximum extraction oil yield.Adopting the optimum conditions,the maximum yield reached 10.01% at 40°C temperature,30 MPa pressure,60 mesh flower powder size,20 L h-1SF-CO 2 flow rate,and 90 min extraction time.The antifungal activities of I.britannica essential oil using the SF-CO 2 against the most important plant pathogenic fungi were also examined through in vitro and in vivo tests.Sixteen plant pathogenic fungi were inhibited to varying degrees at 1 mg mL-1concentration of the essential oil.The mycelial growth of Gaeumannomyces graminis var.tritici was completely inhibited.The radial growths of Phytophthora capsici and Fusarium monilifome were also inhibited by 83.76 and 64.69%,respectively.In addition,the essential oil can inhibit the spore germination of Fusarium oxysporum f.sp.vasinfectum,Phytophthora capsici,Colletotrichum orbiculare,and Pyricularia grisea,and the corresponding inhibition rates were 98.26,96.54,87.89,and 87.35% respectively.The present study has demonstrated that the essential oil of I.britannica flowers extracted through the SF-CO 2 technique is one potential and promising antifungal agent that can be used as botanical fungicide to protect crops.

Laboratory and Field Evaluation of Lupo Compound Miroemulsion(LCM) against Alternaria alternata in Tobacco

[Objective]The paper was to study effect of Lupo compound microemulsion( LCW) on Alternaria alternata. [Method]The activity of spore germination and mycelial growth was investigated by filter paper method and mycelial growth rate method,and field test was also conducted to determine the effect of LCW on tobacco plants. [Result]LCW could inhibit spore germination and mycelial growth of A. alternate. The higher concentration led to more severe reduction of sporulation and heavier inhibition against mycelial growth. When LCW was diluted into 200 times,inhibition rate of sporulation reached 91. 23%,and the inhibition rate of mycelial growth reached 93. 50%. Field test also proved that LCW had significant inhibitory effect on tobacco brown spot disease. [Conclusion]The study provided the reference for using botanical pesticide to control A. alternate in fields.