白术叶斑病菌草茎点霉的生物学特性、药剂筛选及田间防效研究

Study on the Biological Characteristics, Insecticide Screening and Field Control Effect of Leaf Spot Bacteria Phoma herbarum in Atractylodes macrocephala

目的:测定白术叶斑病菌草茎点霉的生物学特性,筛选室内化学杀菌剂,同时进行田间防效研究。方法:用十字交叉法分别测定了不同碳、氮源和pH值的菌落生长直径,用菌丝生长速率法测定了白术草茎点霉对10种杀菌剂的敏感性,开展田间试验测定了防治效果。结果:各碳源对菌丝生长无显著性差异,以牛肉浸膏、硝酸钾作为氮源的菌丝生长较快,且菌丝生长的最适pH值为6~7。500 g/L异菌脲悬浮剂、50%咯菌腈可湿性粉剂、10%苯醚甲环唑水分散粒剂3种杀菌剂对草茎点霉的毒力最强,EC;均小于1 mg/L。同时,田间试验末次施药20 d后,3种杀菌剂的防治效果较好,均高于90%,且各杀菌剂对白术的生长无显著性影响。结论:该病原菌生长的最适氮源为牛肉浸膏,最适pH值为6~7,500 g/L异菌脲悬浮剂、50%咯菌腈可湿性粉剂、10%苯醚甲环唑水分散粒剂3种杀菌剂的抑菌效果和田间防效较好,可作为白术叶斑病的主推药剂试用。

Objective:To determine the biological characteristics of Phoma herbarum of Atractylodes macrocephala leaf spot bacteria,to screen indoor chemical fungicides and study the control effect in field.Methods:The diameters of colony growth with different carbon,nitrogen sources and pH values were determined by cross crossing method.The sensitivities of Phoma herbarum in Atractylodes macrocephala to 10 fungicides were determined by mycelium growth rate method.Field experiments were carried out to determine the control effect.Results:Each carbon source had no significant difference in the growth of mycelia.The mycelia with beef extract and potassium nitrate as the nitrogen source grew faster and the optimum pH value for mycelia growth was 6 to 7.Three fungicides,500 g/L iprodione suspending agent,50%fludioxonil wettable powder and 10%difenoconazole water dispersible granule,had the strongest toxicity to Phoma herbarum,with EC;less than 1 mg/L.At the same time,the control effect of the three fungicides was better 20 days after the last application in the field experiment,all of which were higher than 90%,and each fungicide had no significant effect on the growth of Atractylodes macrocephala.Conclusion:The optimum nitrogen source for the growth of this pathogen is beef extract,and the optimum pH value is 6 to 7.Three fungicides,500 g/L iprodione suspending agent,50%fludioxonil wettable powder and 10%difenoconazole water dispersible granule show good bacteriostatic effect and field control effect and can be used as the main agents of Atractylodes macrocephala leaf spot bacteria.