McDonald S J, Averell R M, Glass M E, Young H M, Mysliwiec T H, Sanford D L, Fidanza M A
Turfgrass Disease Solutions, Spring City, PA.
Division of Science, Pennsylvania State University, Reading.
Plant Dis. 2010 Nov;94(11):1379. doi: 10.1094/PDIS-04-10-0274.
In mid-November 2009, thin, yellow, and irregular-shaped scalloped rings 10 to 25 cm in diameter were observed on 5 to 10% of a golf course putting green in Charles Town, WV. The 20-year-old USGA-specification sand-based green was mowed at 3.1-mm height and consisted of 60% annual bluegrass (Poa annua L.) and 40% creeping bentgrass (Agrostis stoloniferous L. 'Putter'). Minimum and maximum daily air temperature ranged from 2 to 22°C, respectively, with 38 mm of rainfall during the appearance of rings symptoms. Only affected annual bluegrass plants exhibited a peculiar yellow chlorosis of the upper and lower leaves. A single fungal isolate was obtained from active mycelium found within symptomatic annual bluegrass leaves and grown on potato dextrose agar (PDA) amended with chloramphenicol (0.1 g/liter). Fungal colony morphology (i.e., light yellow with irregular-shaped 2- to 4-mm-diameter sclerotia first appearing off-white but progressing to brown by 21 to 28 days in culture) and sequencing of the internal transcribed spacer (ITS) 5.8S rDNA region with primers ITS1 and ITS4 confirmed the isolate as Waitea circinata var. circinata (Warcup & Talbot) with ≥99% sequence identity with GenBank Accession No. FJ755889 (1,2,4). To confirm pathogenicity, a 6-mm-diameter plug of the isolate was removed from the expanding edge of a 4-day-old culture grown on PDA and placed in contact with the lower leaves of 12-week-old annual bluegrass (0.001 g of surface-sterilized seed per cm) grown in 5- × 5-cm plastic pots of autoclaved 85% sand and 15% potting soil. Six pots were inoculated with the isolate and six pots were inoculated with an isolate-free agar plug and then placed in a moist chamber at 28°C. Leaf chlorosis and aerial mycelium was observed in all six inoculated pots 8 to 10 days after inoculation, and symptoms were similar to those expressed in the field. All noninoculated plants remained healthy and asymptomatic. W. circinata var. circinata was reisolated from symptomatic leaves and again confirmed by colony traits and sequencing of the ITS-5.8S rDNA region and submitted as GenBank Accession No. HM807582. To our knowledge, this is the first report of brown ring patch in West Virginia and could be economically important because of intensive fungicide practices used to maintain high-quality putting greens on golf courses (3). References: (1) C. Chen et al. Plant Dis. 91:1687, 2007. (2) K. de la Cerda et al. Plant Dis. 91:791, 2007. (3) J. Kaminski and F. Wong. Golf Course Manage. 75:98, 2007. (4) T. Toda et al. Plant Dis. 89:536, 2005.
2009年11月中旬，在西弗吉尼亚州查尔斯镇一个高尔夫球场果岭的5%至10%区域内，观察到了直径为10至25厘米的薄、黄色且形状不规则的扇形环。这个有着20年历史的符合美国高尔夫球协会标准的沙基果岭，修剪高度为3.1毫米，由60%的一年生早熟禾（Poa annua L.）和40%的匍匐翦股颖（Agrostis stoloniferous L. 'Putter'）组成。每日最低和最高气温分别为2至22°C，在出现环形症状期间降雨量为38毫米。只有受影响的一年生早熟禾植株的上部和下部叶片出现了奇特的黄化现象。从有症状的一年生早熟禾叶片中发现的活跃菌丝体上获取了一个单一真菌分离株，并将其接种在添加了氯霉素（0.1克/升）的马铃薯葡萄糖琼脂（PDA）上进行培养。真菌菌落形态（即浅黄色，带有直径2至4毫米的不规则形状菌核，最初呈灰白色，但在培养21至28天后变为褐色）以及使用引物ITS1和ITS4对内部转录间隔区（ITS）5.8S rDNA区域进行测序，证实该分离株为圆形旋孢腔菌圆孢变种（Waitea circinata var. circinata (Warcup & Talbot)），与GenBank登录号FJ755889的序列同一性≥99%（参考文献1、2、4）。为了确认致病性，从在PDA上生长4天的培养物的扩展边缘取下一个直径6毫米的该分离株菌块，将其与生长在装有经高压灭菌的85%沙子和15%盆栽土的5×5厘米塑料盆中的12周龄一年生早熟禾（每厘米0.001克表面灭菌种子）的下部叶片接触。六个盆接种该分离株，六个盆接种无分离株的琼脂块，然后将它们置于28°C的保湿箱中。接种后8至10天，在所有六个接种盆中都观察到了叶片黄化和气生菌丝体，症状与田间表现相似。所有未接种的植株保持健康且无症状。从有症状的叶片中再次分离出圆形旋孢腔菌圆孢变种，并通过菌落特征和ITS - 5.8S rDNA区域测序再次确认，其GenBank登录号为HM807582。据我们所知，这是西弗吉尼亚州首次关于褐环斑病的报道，由于在高尔夫球场用于维护高质量果岭的大量杀菌剂使用，该病可能具有经济重要性（参考文献3）。参考文献：（1）C. Chen等人，《植物病害》91:1,687，2007年。（2）K. de la Cerda等人，《植物病害》91:791，2007年。（3）J. Kaminski和F. Wong，《高尔夫球场管理》75:98，2007年。（4）T. Toda等人，《植物病害》89:536，2005年。
