R J Aguirre, A H Williams, G N Montes, Cortinas-Escobar H M
Instituto Nacional de Investigaciones Forestales, Agricolas y Pecuarias. P.O. Box 70, Progreso, TX 78579.
Plant Dis. 1997 Jul;81(7):831. doi: 10.1094/PDIS.1997.81.7.831C.
In the winter of 1996-1997 ergot was observed in sorghum (Sorghum bicolor) plants growing in several locations of Tamaulipas, Mexico, including San Fernando, Soto La Marina, Manuel, Cuahutemoc, and Altamira. The disease in sorghum plants was associated with high humidity and low temperatures during the blooming stage in February, 1997. The most obvious symptom was the exudation of honeydew from the infected flowers. Microscopic analysis of the honeydew revealed the presence of the asexual conidia of a Claviceps sp. The abundance, size, and shape of conidia were characteristic of Sphacelia sorghi (1). Honeydew was also observed in plants of Sorghum halepense, forage sorghum and volunteer plants of sorghum, which are also hosts. The first report of ergot in the Americas was made in 1995 in Brazil (2), where it was probably introduced via contaminated seed from Africa. The disease spread rapidly from Brazil to Argentina, Bolivia, Colombia, Paraguay, and Venezuela. The pathogen was probably dispersed and introduced to Mexico by contaminated seed, wind, or insects from South America. The disease represents a serious threat to the 800,000 ha of sorghum grown in Tamaulipas. Due to its confirmed extraordinary capacity to spread rapidly, ergot could affect sorghum growing in regions adjacent to Tamauli-pas, including Nuevo Leon in Mexico, and Texas in the U.S. References: (1) D. E. Frederickson et al. Mycol. Res. 95:1101, 1991. (2) E. M. Reis et al. Plant Dis. 80:463, 1996.
1996 - 1997年冬季，在墨西哥塔毛利帕斯州的几个地方，包括圣费尔南多、索托拉马里纳、曼努埃尔、夸乌特莫克和阿尔塔米拉，生长的高粱（Sorghum bicolor）植株上发现了麦角病。1997年2月开花期高粱植株上的这种病害与高湿度和低温有关。最明显的症状是受感染花朵分泌蜜露。对蜜露进行显微镜分析发现了一种麦角菌无性分生孢子的存在。分生孢子的数量、大小和形状具有高粱散黑粉菌（Sphacelia sorghi）的特征（1）。在假高粱、饲用高粱和高粱自生植株上也观察到了蜜露，这些也是寄主。1995年在巴西首次报道了美洲的麦角病（2），该病可能是通过来自非洲的受污染种子传入的。这种病害从巴西迅速传播到阿根廷、玻利维亚、哥伦比亚、巴拉圭和委内瑞拉。病原体可能是通过来自南美洲的受污染种子、风或昆虫传播并传入墨西哥的。这种病害对塔毛利帕斯州种植的80万公顷高粱构成严重威胁。由于其已被证实的迅速传播的非凡能力，麦角病可能会影响到与塔毛利帕斯州相邻地区种植的高粱，包括墨西哥的新莱昂州和美国的得克萨斯州。参考文献：（1）D. E. Frederickson等人，《真菌学研究》95:1101，1991年。（2）E. M. Reis等人，《植物病害》80:463，1996年。
