Swift C E, Blessinger A, Brandt N, Tisserat N
Tri River Area Extension, Colorado State University, Grand Junction 81503.
Department of Bioagricultural Sciences and Pest Management, Colorado State University, Ft. Collins 80523.
Plant Dis. 2007 Nov;91(11):1519. doi: 10.1094/PDIS-91-11-1519A.
The ectotrophic, root-infecting fungus Magnaporthe poae is the cause of summer patch of Kentucky bluegrass (Poa pratensis). The disease is widely distributed in the mid-Atlantic Region of the United States and west to central Nebraska and Kansas (2). It also has been found in certain locations of Washington and California (2) but has not been confirmed in the Rocky Mountain Region. In August 2005 and 2006, tan patches and rings of dead turf ranging from 10 to 30 cm in diameter were observed in Kentucky bluegrass swards in Grand Junction and Greeley, CO, respectively. The sites, separated by approximately 360 km, are located west and east of the Continental Divide. A network of ectotrophic hyphae were observed on diseased root segments collected from both sites. A fungus morphologically similar to M. poae (2) was consistently isolated from these segments. DNA was extracted from mycelium of one isolate from each location and amplified by PCR with the M. poae species-specific primers MP1 and MP2 (1). A 453-bp DNA fragment was consistently amplified from DNA of both isolates, diagnostic of M. poae. To our knowledge, this is the first report of summer patch in Colorado and indicates that M. poae may be widely distributed in the central Rocky Mountain Region. References: (1) T. E. Bunting et al. Phytopathology 86:398, 1996. (2) B. B. Clarke and A. B. Gould, eds. Turfgrass Patch Diseases Caused by Ectotrophic Root-Infecting Fungi. The American Phytopathological Society, St. Paul, MN, 1993.
外生型、侵染根部的真菌早熟禾角斑病菌是草地早熟禾夏季斑病的病原菌。该病广泛分布于美国大西洋中部地区，向西至内布拉斯加州中部和堪萨斯州（2）。在华盛顿州和加利福尼亚州的某些地方也发现了该病（2），但在落基山脉地区尚未得到证实。2005年8月和2006年，分别在科罗拉多州大章克申和格里利的草地早熟禾草皮中观察到直径为10至30厘米的黄褐色斑块和死亡草皮环。这两个地点相距约360公里，分别位于大陆分水岭的西侧和东侧。在从这两个地点采集的患病根段上观察到了外生菌丝网络。从这些根段中始终分离出一种形态上与早熟禾角斑病菌相似的真菌（2）。从每个地点的一个分离株的菌丝体中提取DNA，并用早熟禾角斑病菌种特异性引物MP1和MP2进行PCR扩增（1）。从两个分离株的DNA中始终扩增出一个453bp的DNA片段，这是早熟禾角斑病菌的诊断片段。据我们所知，这是科罗拉多州夏季斑病的首次报道，表明早熟禾角斑病菌可能在落基山脉中部地区广泛分布。参考文献：（1）T.E.邦廷等人，《植物病理学》86:398，1996年。（2）B.B.克拉克和A.B.古尔德编，《由外生型侵染根部真菌引起的草坪草斑块病害》。美国植物病理学会，明尼苏达州圣保罗，1993年。
