枣缩果病初侵染互隔链格孢菌抗药性研究

摘要

为了解互隔链格孢菌对异菌脲和苯甲丙环唑的抗药性现状,以确定防治枣缩果病的最有效的施药方案,采用菌丝生长速率法,测定了枣缩果病初侵染互隔链格孢菌的4个菌株(CN191、CN192、CN193和CN194)对这2种药剂的敏感性;从中选取对这2种药剂最为敏感的菌株进行抗药性筛选,并以筛选到的抗药菌株为试验对象,测定其对另一种药剂的敏感性.2016和2017年,采用这2种药剂,在林间施用过和未施用过这2种药剂的枣园进行防治试验,并于发病初期和盛期调查发病率.结果表明:CN194对这2种药剂都很敏感,经诱导后得到稳定的抗异菌脲突变体CN194y,与苯甲丙环唑没有交互抗性.在施用过这2种药剂的林间,苯甲丙环唑的防治效果较好,分别为81.3%和51.3%;在未施用过这2种药剂的林间,异菌脲的防治效果较好,分别为92.9%和68.4%.不同地区枣缩果病菌对异菌脲和苯甲丙环唑的敏感性各异,但敏感趋势相同;互隔链格孢菌对异菌脲易产生抗药性,而对苯甲丙环唑不易产生抗药性,且2种药剂之间不产生交互抗性.林间防治以异菌脲和苯甲丙环唑交替施用方案为佳.%To investigate resistance of Alternaria alternata,the unique pathogen causing jujube shrunken-fruit disease (JSFD), to iprodione and benzoyl propiconazole, and to determine the most effective method for jujube shrunken-fruit disease, four strains (CN191, CN192, CN193 and CN194) were used to for testing their sensitivities to the two fungicides with the method of mycelial growth rate. The most sensitive strain to the two fungicides was screened, and the obtained resistant strain to one fungicide was tested for its resistance to another fungicide.In 2016 and 2017,field control experiments were performed using the two fungicides, which were previously applied or never applied, and disease incidences were recorded at the early stage and peak period of disease development. The results show that CN194 was the most sensitive strain to both fungicides, and after induction, a stable iprodione-resistant mutant strain, designated as CN194y, was obtained. No cross resistance to benzoyl propiconazole in strain CN194y was found. The control effects of benzoyl propiconazole were 81.3% and 51.3% respectively, better than that of iprodione in the jujube plantations, in which the two fungicides were previously sprayed. However, the control effects of iprodione reached 92.9% and 68.4% respectively, higher than that of benzoyl propiconazole in the jujube plantations, in which the two fungicides were never applied previously.The sensitivities of A.alternata to iprodione and benzoyl propiconazole were different in different regions,but the sensitive trends were the same.A.alternata was inclined to appearing resistant mutants to iprodione,but not to benzoyl propiconazole,and there was no cross resistance for A.alternata to the two fungicides.In conclusion,the two fungicides had better be applied alternately in jujube fields for effective control of JSFD.