Wise K A, Bradley C A, Pasche J S, Gudmestad N C, Dugan F M, Chen W
Department of Plant Pathology, North Dakota State University, Fargo 58105.
United States Department of Agriculture-Agriculture Research Service, Department of Plant Pathology, Washington State University, Pullman 99164.
Plant Dis. 2008 Feb;92(2):295-300. doi: 10.1094/PDIS-92-2-0295.
Ascochyta rabiei, causal agent of Ascochyta blight on chickpea (Cicer arietinum), can cause severe yield loss in the United States. Growers rely on applications of fungicides with site-specific modes of action such as the quinone outside inhibiting (QoI) fungicides azoxystrobin and pyraclostrobin, and the carboximide fungicide boscalid, to manage disease. In all, 51 isolates collected prior to QoI fungicide registration and 71 isolates collected prior to boscalid registration in the United States were tested in an in vitro assay to determine the effective fungicide concentration at which 50% of conidial germination was inhibited (EC) for each isolate-fungicide combination. The effect of salicylhydroxamic acid (SHAM) on conidia of A. rabiei in the presence and absence of azoxystrobin also was assessed to determine whether the fungus is capable of using alternative respiration. Five of nine A. rabiei isolates tested had significantly higher (P ≤ 0.05) EC values when SHAM was not included in media amended with azoxystrobin, indicating that A. rabiei has the potential to use alternative respiration to overcome fungicide toxicity in vitro. EC values of azoxystrobin and pyraclostrobin ranged from 0.0182 to 0.0338 μg/ml and from 0.0012 to 0.0033 μg/ml, with mean values of 0.0272 and 0.0023 μg/ml, respectively. EC values of boscalid ranged from 0.0177 to 0.4960 μg/ml, with a mean of 0.1903 μg/ml. Establishment of these baselines is the first step in developing a monitoring program to determine whether shifts in sensitivity to these fungicides are occurring in the A. rabiei pathogen population.
鹰嘴豆褐斑病菌（Ascochyta rabiei）是鹰嘴豆（Cicer arietinum）上褐斑病的病原菌，在美国可导致严重的产量损失。种植者依靠使用具有特定作用位点的杀菌剂来防治病害，如醌外抑制剂（QoI）类杀菌剂嘧菌酯和吡唑醚菌酯，以及甲氧基丙烯酸酯类杀菌剂啶酰菌胺。在美国，对51株在QoI类杀菌剂登记前收集的菌株和71株在啶酰菌胺登记前收集的菌株进行了体外试验，以确定每种菌株 - 杀菌剂组合抑制50%分生孢子萌发的有效杀菌剂浓度（EC）。还评估了水杨羟肟酸（SHAM）在有和没有嘧菌酯存在的情况下对鹰嘴豆褐斑病菌分生孢子的影响，以确定该真菌是否能够利用交替呼吸。在用嘧菌酯改良的培养基中不添加SHAM时，测试的9株鹰嘴豆褐斑病菌中有5株的EC值显著更高（P≤0.05），这表明鹰嘴豆褐斑病菌有可能利用交替呼吸在体外克服杀菌剂毒性。嘧菌酯和吡唑醚菌酯的EC值范围分别为0.0182至0.0338μg/ml和0.0012至0.0033μg/ml，平均值分别为0.0272和0.0023μg/ml。啶酰菌胺的EC值范围为0.0177至0.4960μg/ml，平均值为0.1903μg/ml。建立这些基线是制定监测计划的第一步，该计划用于确定鹰嘴豆褐斑病菌种群对这些杀菌剂的敏感性是否发生变化。
