Shandong Institute of Pomology, Tai'an, Shandong, 271000, China.
College of Plant Protection, Shandong Agricultural University, Tai'an, Shandong 271018, China.
Plant Dis. 2022 Nov;106(11):2817-2822. doi: 10.1094/PDIS-01-22-0053-RE. Epub 2022 Oct 9.
China has the largest acreage and is the greatest producer of apples in the world. Apple ring rot (ARR) caused by is one of the major diseases affecting apple fruit production. Tebuconazole, a sterol demethylation-inhibiting (DMI) fungicide, has been increasingly applied to manage ARR in China. Resistance to tebuconazole in field populations of may be selected and accumulate to higher degrees over time. Establishment of tebuconazole sensitivity monitoring programs is critically important for resistance management and effective ARR control. However, the resistance level of to tebuconazole in China remains largely unknown. In this study, in vitro mycelial growth assays of in media amended with tebuconazole were conducted, and the sensitivity of to tebuconazole was determined with a set of 390 isolates collected from the major apple production provinces in China between 2006 and 2014. Results showed that the 50% effective concentration (EC) value ranged from 0.011 to 0.918, 0.040 to 1.621, and 0.052 to 1.925 μg ml with a median value of 0.194, 0.386, and 0.782 μg ml in the isolates collected in 2006, 2010, and 2014, respectively. The frequency distribution of EC for tebuconazole was a nonnormal distribution ( < 0.05), suggesting that subpopulations with reduced sensitivity to tebuconazole had emerged in these isolates. The frequency distribution of the isolates collected in 2006 fit a unimodal curve and could be regarded as the baseline sensitivity to tebuconazole. The resistance levels increased over time with the average occurrence frequency of 43.3% and resistance index of 0.38. Positive cross-resistance was observed between tebuconazole and metconazole, which is another DMI fungicide, but multiple resistance was not detected between tebuconazole and non-DMI fungicides. Our results demonstrated that regular long-term resistance monitoring combining with prudent fungicide use should be implemented to prolong the lifespan of tebuconazole in management of ARR in apples.
中国是世界上苹果种植面积最大、产量最多的国家。由 引起的苹果轮纹病是影响苹果果实生产的主要病害之一。三唑酮，一种甾醇脱甲基抑制剂（DMI）杀菌剂，已越来越多地应用于中国防治苹果轮纹病。田间种群对三唑酮的抗性可能会随着时间的推移而被选择和积累到更高的程度。建立三唑酮敏感性监测计划对于抗性管理和有效防治苹果轮纹病至关重要。然而，中国对 对三唑酮的抗性水平在很大程度上仍然未知。本研究采用含有三唑酮的培养基对 进行了离体菌丝生长测定，并对 2006 年至 2014 年期间从中国主要苹果生产省份采集的 390 个分离株进行了三唑酮敏感性测定。结果表明，2006 年、2010 年和 2014 年采集的分离物的 50%有效浓度（EC）值范围分别为 0.011 至 0.918、0.040 至 1.621 和 0.052 至 1.925μgml，中位数分别为 0.194、0.386 和 0.782μgml。三唑酮 EC 的频率分布呈非正态分布（ < 0.05），表明这些分离物中已经出现了对三唑酮敏感性降低的亚种群。2006 年采集的 分离物的频率分布符合单峰曲线，可以视为三唑酮的基线敏感性。随着时间的推移，抗性水平不断上升，平均出现频率为 43.3%，抗性指数为 0.38。三唑酮和另一种 DMI 杀菌剂戊唑醇之间存在正向交叉抗性，但在三唑酮和非 DMI 杀菌剂之间未检测到多重抗性。研究结果表明，应结合谨慎使用杀菌剂，定期进行长期抗性监测，以延长三唑酮在防治苹果轮纹病中的使用寿命。
