van Jaarsveld L C, Kriel W-M, Minnaar A
Department of Plant Sciences, University of the Free State, P.O. Box 399, Bloemfontein 9300, South Africa.
Plant Dis. 2006 Jan;90(1):113. doi: 10.1094/PD-90-0113C.
Canna indica L., known as Indian shot or canna lily, occurs throughout the New World in tropical and subtropical areas. This upright, perennial, rhizomatous herb is a popular garden plant in South Africa because of its spectacular plant habit and growth vigor. During January 2005, canna lily leaves with rust symptoms were collected from Pietermaritzburg in the province of KwaZulu-Natal. Orange-yellow uredinia were observed primarily on the abaxial surfaces, often covering the entire leaf with coalescing pustules. Koch's postulates were completed in repeated tests with spray inoculations of blooming potted plants, urediniospores suspended in water (42 × 10 spores/ml), incubation in a dew chamber for 14 h at 20°C in the dark, and then returned to the greenhouse. Symptoms similar to those of the original collection formed 10 days postinoculation. Only the uredinial stage was observed, which was characterized by hypophyllous, yellow-brown, subepidermal, erumpent, and irregular shaped uredinia. The urediniospores were round to ovoid, orange-yellow, echinulate, and 25 to 35 × 15 to 20 μm. The pathogen was identified as Puccinia thaliae Diet. according to its description on Canna edulis Ker-Gawl. (1). Following the report of P. thaliae on C. indica in Hawaii in 1989 (2), to our knowledge, this is the first description of canna lily rust in South Africa. References: (1) M. L. Jeeva et al. Plant Pathol. 53:261, 2004. (2) D. E. Gardner and C. S. Hodges. Pac. Sci. 43:4155, 1989.
美人蕉，又称印度射干或美人蕉百合，分布于新世界的热带和亚热带地区。这种直立的多年生根茎草本植物因其壮观的植株形态和生长活力，在南非是一种受欢迎的园林植物。2005年1月，从夸祖鲁 - 纳塔尔省的彼得马里茨堡采集到有锈病症状的美人蕉百合叶片。橙黄色的夏孢子堆主要出现在叶片背面，常常融合成疱斑覆盖整个叶片。通过对盛开的盆栽植物进行喷雾接种来重复完成柯赫氏法则验证，将夏孢子悬浮于水中（42×10个孢子/毫升），在黑暗中于20°C的露室中培养14小时，然后放回温室。接种后10天形成了与原始采集样本相似的症状。只观察到了夏孢子阶段，其特征为叶下生、黄褐色、表皮下生、突破表皮且形状不规则的夏孢子堆。夏孢子圆形至卵形，橙黄色，具刺，大小为25至35×15至20微米。根据对食用美人蕉（Canna edulis Ker - Gawl.）的描述，该病原菌被鉴定为塔利亚柄锈菌（Puccinia thaliae Diet.）。（1）继1989年夏威夷报道塔利亚柄锈菌侵染美人蕉之后（2），据我们所知，这是南非首次对美人蕉锈病的描述。参考文献：（1）M. L. Jeeva等人，《植物病理学》53:261，2004年。（2）D. E. Gardner和C. S. Hodges，《太平洋科学》43:4155，1989年。
