1Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI 53706.
2Wine and Viticulture Department, California Polytechnic State University, San Luis Obispo, CA 93407.
Phytopathology. 2019 Aug;109(8):1425-1432. doi: 10.1094/PHYTO-10-18-0381-R. Epub 2019 Jul 1.
Early blight caused by and brown spot caused by are two common foliar diseases of potato, with early blight typically predominating in incidence and severity. Renewed interest in these two diseases has arisen as a result of notable differences in fungicide resistance profiles of the pathogens and inconsistent outcomes of disease management tactics. The pathogens share similar disease cycles, but they differ in the shape and size of their conidia. has a host range that includes just the Solanaceae, whereas has a broad host range spanning numerous plant families. Such differences may result in differences in dispersal of the pathogens and subsequently influence epidemiology and management outcomes. In the commercial potato fields investigated in this study, the aerial conidial concentrations of and differed significantly, with those of conidia being higher in number and more variable than those of The aerial conidial concentration of almost always significantly decreased with height (0 to 3 m above the canopy), whereas such a decrease was only observed for 4 of 12 days for . The atmospheric concentrations of were higher than those of at both upwind and downwind edges of the field ( < 0.0001), indicating more potential for long-distance dispersal. A higher aerial concentration of conidia at the downwind than the upwind location was observed for ( < 0.05), whereas overall no such effect was observed for . This indicated that the potato fields investigated were likely the source of conidia, but they may not be the sole source of . Results are consistent with inoculum of coming primarily from within the potato crop, whereas that of may be generated from diverse plant sources across the landscape.
早疫病由引起，褐斑病由引起，这两种是马铃薯叶片的两种常见病害，其中早疫病的发病率和严重程度通常更为突出。由于病原菌对杀菌剂的抗性谱存在显著差异，以及疾病管理策略的结果不一致，人们对这两种病害重新产生了兴趣。病原菌具有相似的病害循环，但它们在分生孢子的形状和大小上有所不同。 仅包括茄科植物，而 则具有广泛的宿主范围，涵盖许多植物科。这种差异可能导致病原菌的传播方式不同，从而影响流行病学和管理结果。在本研究调查的商业马铃薯田中， 和 的气传分生孢子浓度存在显著差异， 分生孢子的数量更多且更具变异性。 的气传分生孢子浓度几乎总是随着高度（距树冠 0 至 3 米）显著降低，而 只有 4 天观察到这种降低。田间的 和 的大气浓度均以上风向和下风向边缘处高于下风处（ < 0.0001），表明有更多的远距离传播潜力。 在下风向处的气传分生孢子浓度高于上风向处（ < 0.05），而 总体上没有观察到这种效应。这表明调查的马铃薯田可能是 的分生孢子的来源，但它们可能不是 的唯一来源。结果与 主要来自马铃薯作物内部的接种体一致，而 的接种体可能来自景观中的多种植物源。
