粉锈宁防治甘薯黑斑病初步研究

粉锈宁以高于277ppm(25％粉锈宁900倍液)浓度,对甘薯黑斑病有良好的防效。在接菌3小时后,用此浓度药液浸薯片或薯块10分钟,药效达99％。277ppm药液浸薯片10分钟,5天后接菌,薯片表面不长菌落,1毫米深处尚有一定药效,3毫米深处无效。800ppm药液浸整薯15分钟,4天后接菌,药效作用平均深度1毫米。在无病大田试验,277ppm药液浸带菌薯苗5分钟,防效为84.6％。试验表明,粉锈宁只能通过伤口渗入薯块;浸药后用水冲洗,基本上不影响药效;提高药液温度,可增加药效。部分试验还加入了多菌灵和甲基托布津进行了药效比较。

PRELIMINARY STUDY ON THE CONTROL OF CERATOCYSTIS FIMBRIATA OF SWEETPOTATO BY TRIADIMEFON

Effect to control Ceratocystis fimbriata Ell.et Halst.of sweetpotatoby Triadimefon was good when concentrations of the fungicide werehigher than 277ppm.Percentage of control of the fungus was over 99%when root tubers of sweetpotato or its segments soaked in Triadimefonsolution with 277ppm for 10 minuts 3 hours after inoculation.Thefungus were inhibited fully on the surface of the segments soaked wheninoculated on the fifth day and the inhibition to the fungus was ob-served in the 1mm deep and not in the 3mm deep while the segmentssoaked in the solution for 10 minuts.When root tubers soaked in Tri-adimefon solution with 800ppm for 15 minuts and inoculated by the fun-gus on the fourth day,the effect was observed in 1mm deep.In thenon-diseased field experiments the percentage of inhibition to the fun-gus was 84.6% when seedlings from diseased root tubers soaked in Tri-adimefon solution with 277 ppm for 5 minuts.Triadimefon could per-meate into root tubers of sweetpotato only through wounds.Effect ofthe fungicide was not reduced when the segments soaked with the fun-gicide were washed with water.Higher temperature of the fungicide so-lution could increase the effect to the fungus.