云南省马铃薯银腐病(Helminthosporiumsolani)的研究

20 0 1年我们从云南省薯产区市场上和仓库内采集到马铃薯银腐病标本 ,研究表明 ,该病冬季发病率达 33. 3%。受感染部位多分布于薯块的茎基端 ,重病薯块因失水过多 ,块茎皱缩。病菌生长后期变为棕色。分生孢子梗无分枝 ,大小为 15 0～ 5 5 0× 7 0～ 10 0 μm (平均 35 0× 8 5 μm ) ,1～ 6根成簇着生于球形基部。分生孢子棕色 ,单个或成簇地自分生孢子梗基端往上呈轮状排列 ,直或稍弯 ,顶端小 ,略呈锥形 ,有 3～ 8个横隔 ,大小为 2 0～ 80 μm× 7 5～ 10 μm (平均 5 0× 8 5 μm )。根据该病病原真菌的形态学和培养性状 ,鉴定为茄长蠕孢 (Helminthosporiumsolani)。黑暗和光照下培养 ,分生孢的萌发率无明显差异。通过人工接种于薯块表面 ,表现出较强的致病性 ,马铃薯银腐病在中国属首次报道

OCCURRENCE OF SILVER SCURF DISEASE CAUSED BY HELMINTHOSPORIUM SOLANI (DURIEU & MONT.,) IN YUNNAN PROVINCE

Potato tubers with silver scurf lesions were collected from storage and market potatoes in Yunnan province in the 2001.Incidence of silver scurf disease reached 33 3% from January to April. Symptoms of this disease were mainly confined to the stem end of affected tubers and severely infected tubers shriveled and shrank due to loss of moisture. The causal agent of silver scurf was identified as Helminthosporium solani by mycological and cultural characteristics. Conidiophores are unbrenched and turn to brown with age. The size of conidiophores are 150～550μm×7 0～10～0μm(avg.350×8 5μm)and 1 to 6 conidiophores are clustere in a bulb. Conidia are brown, arranged in whorls arising singly or in groups from the distal ends. Shape of conidia are straight, slightly curved, and have 3 to 8 septate. Size of condia with tapered tip was 20～80μm ×7 5～10μm(avg. 50×8 5μm). Sporulation of conidia was not difference depending on dark or light incubation conditions. Pathogenicity of the fungus was confirmed by artifical inoculation on the tuber surface. This is the first report in China of potato sliver scurf caused by Helminthosporium solani.