La Porta N, Capretti P
Dipartimento di Risorse Naturali e Ambiente, Istituto Agrario S. Michele a/Adige, I-38010 Italy.
Istituto di Patologia e Zoologia Forestale e Agraria, Università di Firenze, I-50144, Italy.
Plant Dis. 2000 Aug;84(8):922. doi: 10.1094/PDIS.2000.84.8.922A.
The pathogen Mycosphaerella dearnessii Barr. (syn. Scirrhia acicola; anamorph Lecanosticta acicola), the causal agent of brown spot needle blight, was observed on Pinus mugo in the Botanical Garden in Gardone (Brescia), on the western side of Garda Lake in northeastern Italy. Symptoms were first noticed in the spring of 1997 by Klaus Lang (University of Freising, Germany). Two years later, all 12 of the P. mugo present in the Garden exhibited extensive necrosis, and defoliation of the crown starting from the bottom upward was more prevalent on the shaded portion of infected trees. The trees were about 50 years old and 2.0 to 2.5 m in height. Symptomatic needles were confined to the 2- and 3-year old internodes. Infected needles had several dark to purplish-brown spots surrounded by green tissue and usually had dead tips. Pycnidia and conidia of Lecanosticta acicola were observed. Conidia were 4-celled, curved, pointed at one end and blunt at the other, pale olive-brown and 20 to 30 × 3 to 4 μm. The fungus was isolated in pure culture. The pathogen causes serious losses in China, eastern United States, and central and South America, but was observed for the first time in Europe only 30 years ago. It is a major cause of needle blight on several European pine species, especially P. sylvestris, P. nigra, and P. mugo. In the last 7 years, there have been reports of the fungus in pine stands, first in France, Aquitaine, and the western Pyrenees on P. radiata (3), and more recently on P. mugo in the Alps in Austria (1), Switzerland (2), and southern Germany (4). This record of the fungus near Lake Garda poses a new serious threat especially for the pine plantations of P. nigra and P. sylvestris in the more humid locations in the Alps, Apennines, and elsewhere in the mountains of southern Europe where the climatic conditions are similar to that of central Europe. This is the first report of M. dearnessii on the southern slopes of the Alps and in Italy. References: (1) M. Brandstetter and T. Cech. Oesterreichische Forstzeitung 110:35, 1999. (2) O. Holdenrieder and T. N. Sieber. Eur. J. For. Pathol. 25:293, 1995. (3) A. Levy and C. Lafaurie. Phytoma 463:33, 1994. (4) L. Pehl L. Nachrichtenbl. Dtsch. Pflanzenschutzdienstes 47:305, 1995.
病原菌Dearnessii盘二孢菌（Barr.）（异名：松针红斑病菌；无性型为松针散斑壳）是松针褐斑病的致病因子，在意大利东北部加尔达湖西侧加尔多内（布雷西亚）植物园的中欧山松上被发现。1997年春季，德国弗赖辛大学的克劳斯·朗首次发现了症状。两年后，植物园内所有12株中欧山松都出现了大面积坏死，树冠从底部向上落叶在受感染树木的背阴部分更为普遍。这些树约50年树龄，高2.0至2.5米。有症状的针叶局限于2年生和3年生节间。受感染的针叶有几个深褐色至紫褐色斑点，周围有绿色组织，通常叶尖枯死。观察到了松针散斑壳的分生孢子器和分生孢子。分生孢子为4细胞，弯曲，一端尖一端钝，浅橄榄褐色，20至30×3至4微米。该真菌被纯培养分离出来。这种病原菌在中国、美国东部以及中美洲和南美洲造成严重损失，但30年前才在欧洲首次被发现。它是几种欧洲松树针叶枯病的主要病因，尤其是欧洲赤松、黑松和中欧山松。在过去7年里，有关于该真菌在松林里出现的报道，首先是在法国阿基坦和西比利牛斯地区的辐射松上（3），最近在奥地利阿尔卑斯山（1）、瑞士（2）和德国南部（4）的中欧山松上也有发现。加尔达湖附近该真菌的这一记录构成了新的严重威胁，特别是对阿尔卑斯山、亚平宁山脉以及南欧山区其他气候条件与中欧相似且湿度较大地区的黑松和欧洲赤松人工林。这是Dearnessii盘二孢菌在阿尔卑斯山南坡和意大利的首次报道。参考文献：（1）M. 布兰德施泰特和T. 切赫。《奥地利林业时报》110:35，1999年。（2）O. 霍尔登里德和T. N. 西贝尔。《欧洲林业病理学杂志》25:293，1995年。（3）A. 利维和平. 拉富里。《植物病害》463:33，1994年。（4）L. 佩尔。《德国植物保护通报》47:305，1995年。
