Guatimosim E, Fuga C A G, Pinto H J, Barreto R W
Departamento de Fitopatologia, Universidade Federal de Viçosa (UFV), 36570-000, Viçosa, MG, Brazil.
Plant Dis. 2011 Dec;95(12):1588. doi: 10.1094/PDIS-05-11-0439.
Bidens sulphurea (synonym Cosmos sulphureus) (Asteraceae), commonly known as yellow cosmos, is a native herbaceous species from Mexico that is widely used as an ornamental. It has been introduced in Brazil and has escaped from gardens, becoming a minor weed in ruderal, crop and pasture areas (2). In June 2010, groups of B. sulphurea individuals were found in a garden at the locality of Piúna, municipality of Viçosa (state of Minas Gerais, Brazil), that were severely attacked by gray mold. The disease led to flower rot with dieback of infected peduncles and stems. Plant tissues became brown to grayish brown and were covered by extensive fungal sporulation; in addition, seeds were colonized and destroyed by the fungus. A hyphomycete was regularly found associated with the diseased flowers, which was readily recognized as having a morphology typical of Botrytis cinerea: conidiophores solitary, cylindrical, terminally branched, 15 to 20 μm wide, grayish to olivaceous gray, and smooth; conidiogenous cells polyblastic, subcylindrical to ampulliform, and 120 to 230 × (13-) 14 to 16 (-19) μm; conidia ellipsoid to obovoid, 8 to 12 × 6.5 to 8 (-9) μm, with a discrete hilum at the base, 1 to 2 μm, aseptate, and hyaline. The fungus was isolated in pure culture and inoculation of one isolate on healthy B. suphurea individuals was carried out with a 2.14 × 10 conidia/ml suspension, which was sprayed to runoff onto three plants bearing four to six inflorescences. All plants were left in a moist chamber for 48 h and later transferred to a bench in a greenhouse at 21 ± 3°C. Gray mold symptoms appeared after 10 days that led to rapid and complete necrosis of flowers and peduncles. Infection first appeared on the flowers but progressed downward, leading to top dieback and finally plant death (not seen in the field). Only Botrytis cinerea was obtained in isolations from diseased flowers, demonstrating the pathogenicity of the fungus. A representative sample was deposited in the UFV herbarium (VIC 31602). The only other record of Botrytis cinerea causing gray mold of B. sulphurea is from China (1,3). To our knowledge, this is the first record of Botrytis cinerea causing gray mold on B. sulphurea in Brazil. References: (1) D. F. Farr and A. Y. Rossman. Fungal Databases. Systematic Botany and Mycology Laboratory, ARS, UDSA. Retrieved from http://nt.ars-grin.gov/fungaldatabases/ , 2011. (2) H. Lorenzi and H. M. Souza. Plantas Ornamentais no Brasil. Plantarum, Nova Odessa, Brazil. 1995. (3) Z. Zhang. Flora Fungorum Sinicorum. Vol. 26. Botrytis, Ramularia. Science Press, Beijing, China. 2006.
硫黄鬼针草（同义词：硫黄波斯菊）（菊科），俗称黄波斯菊，是一种原产于墨西哥的草本植物，广泛用作观赏植物。它已被引入巴西并逸出花园，在荒地、农田和牧场地区成为一种次要杂草（2）。2010年6月，在巴西米纳斯吉拉斯州维索萨市皮乌纳镇的一个花园里发现了几株硫黄鬼针草，它们受到灰霉病的严重侵袭。该病导致花朵腐烂，受感染的花柄和茎枯萎。植物组织变成褐色至灰棕色，并被大量真菌孢子覆盖；此外，种子也被真菌侵染并破坏。经常发现一种丝孢纲真菌与患病花朵相关，很容易识别出它具有灰葡萄孢典型的形态特征：分生孢子梗单生，圆柱形，顶端分枝，宽15至20μm，浅灰色至橄榄灰色，表面光滑；产孢细胞多芽生，近圆柱形至壶形，120至230×（13 -）14至16（-19）μm；分生孢子椭圆形至倒卵形，8至12×6.5至8（-9）μm，基部有一个明显的脐点，1至2μm，无隔膜，透明。该真菌被纯培养分离出来，并用浓度为2.14×10个分生孢子/毫升的悬浮液将一个分离株接种到健康的硫黄鬼针草植株上，将悬浮液喷洒到三株带有四到六个花序的植株上直至径流。所有植株都放在潮湿的培养箱中48小时，然后转移到温度为21±3°C的温室中的长凳上。10天后出现灰霉病症状，导致花朵和花柄迅速完全坏死。感染首先出现在花朵上，但向下发展，导致顶部枯萎，最终植株死亡（在田间未观察到）。从患病花朵中分离培养仅得到灰葡萄孢，证明了该真菌的致病性。一个代表性样本保存在UFV植物标本馆（VIC 31602）。关于灰葡萄孢引起硫黄鬼针草灰霉病的唯一其他记录来自中国（1,3）。据我们所知，这是巴西首次记录到灰葡萄孢引起硫黄鬼针草灰霉病。参考文献：（1）D.F.法尔和A.Y.罗斯曼。真菌数据库。系统植物学和真菌学实验室，美国农业部农业研究局。从http://nt.ars-grin.gov/fungaldatabases/获取，2011年。（2）H.洛伦齐和H.M.苏扎。巴西的观赏植物。Plantarum，巴西新敖德萨。1995年。（3）张泽。中国真菌志。第26卷。葡萄孢属、柱隔孢属。科学出版社，中国北京。2006年。
