Department of Plant Sciences/Crop Development Centre, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5A8, Canada.
Agriculture and Agri-Food Canada, Melfort, Saskatchewan S0E 1A0, Canada.
Plant Dis. 2021 Jun;105(6):1677-1684. doi: 10.1094/PDIS-06-20-1175-RE. Epub 2021 May 5.
Among the diseases that have the potential to cause damage to flax ( L.) every year, the fungal disease pasmo, caused by , is the most important. Fungicide application and a diverse crop rotation are the most important strategies to control this disease because there is little variation in resistance among flax cultivars. However, few fungicide products are available to flax growers. Field studies were conducted at four locations in Western Canada in 2014, 2015, and 2016 to determine the effect of two fungicide active ingredients applied singly and in combination: pyraclostrobin, fluxapyroxad, and fluxapyroxad + pyraclostrobin; and two application timings (early-flower, mid-flower, and at both stages) on pasmo disease severity, seed yield, and quality of flaxseed. The results indicated that among the three fungicide treatments, both pyraclostrobin and fluxapyroxad + pyraclostrobin controlled pasmo effectively; however, fluxapyroxad + pyraclostrobin was the most beneficial to improve the quality and quantity of the seed for most of the site-years. Disease severity in the fungicide-free control was 70%, and application of fluxapyroxad + pyraclostrobin decreased disease severity to 18%, followed by pyraclostrobin (23%) and fluxapyroxad (48%). Application of fluxapyroxad + pyraclostrobin also improved seed yield to 2,562 kg ha compared with 1,874 kg ha for the fungicide-free control, followed by pyraclostrobin (2,391 kg ha) and fluxapyroxad (2,340 kg ha). Fungicide application at early and mid-flowering stage had the same effects on disease severity and seed yield; however, seed quality was improved more when fungicide was applied at mid-flowering stage. Continuous use of the same fungicide may result in the development of fungicide insensitivity in the pathogen population. Thus, sensitivity of isolates to pyraclostrobin and fluxapyroxad fungicides was determined by the spore germination and microtiter assay methods. Fungicide insensitivity was not detected among the 73 isolates of tested against either of these fungicides.
在每年可能对亚麻（Linum usitatissimum）造成损害的疾病中，由 引起的真菌病害 pasmo 最为重要。使用杀菌剂和多样化的轮作是控制这种疾病的最重要策略，因为亚麻品种之间的抗性差异很小。然而，可供亚麻种植者使用的杀菌剂产品很少。2014 年、2015 年和 2016 年，在加拿大西部的四个地点进行了田间研究，以确定单独和组合使用两种杀菌剂活性成分（pyraclostrobin、fluxapyroxad 和 fluxapyroxad + pyraclostrobin）以及两种施药时间（初花期、盛花期和两个阶段）对 pasmo 疾病严重程度、种子产量和亚麻籽质量的影响。结果表明，在三种杀菌剂处理中，pyraclostrobin 和 fluxapyroxad + pyraclostrobin 都能有效控制 pasmo；然而，fluxapyroxad + pyraclostrobin 最有利于提高大多数地点-年份的种子质量和数量。无杀菌剂对照的疾病严重程度为 70%，施用 fluxapyroxad + pyraclostrobin 可将疾病严重程度降低至 18%，其次是 pyraclostrobin（23%）和 fluxapyroxad（48%）。施用 fluxapyroxad + pyraclostrobin 还将种子产量提高到 2562 公斤/公顷，而无杀菌剂对照的产量为 1874 公斤/公顷，其次是 pyraclostrobin（2391 公斤/公顷）和 fluxapyroxad（2340 公斤/公顷）。在初花期和盛花期施用杀菌剂对疾病严重程度和种子产量有相同的影响；然而，在盛花期施用杀菌剂时，种子质量得到了更大的改善。连续使用相同的杀菌剂可能会导致病原菌种群对杀菌剂产生抗药性。因此，通过孢子萌发和微量滴定法测定了 73 个 分离株对 pyraclostrobin 和 fluxapyroxad 杀菌剂的敏感性。在测试的 73 个 分离株中，没有一个对这两种杀菌剂表现出抗药性。
