水稻叶尖枯病初侵染和再侵染研究

THE PRIMARY AND SECONDARY INFECTIONS OF RICE PHYLLOSTICTA LEAF BLIGHT

本研究首次证明水稻叶尖枯病(Phyllosticta oryzicola Hara)的初侵染来源与病残体、病稻种和带菌野生杂草有关。在老病区,病残体特别是落在田中的病叶是主要的初侵染来源。病区稻种带菌率一般为0.5～2.5％,带菌部位几乎都是颖壳。田间无芒稗、西来稗、双穗雀稗、狗尾草、李氏禾、千金子、牛筋草、虎尾草、白茅、菰、马唐和芦竹等10多种禾本科杂草均可是病菌的野生寄主。试验还表明,田间水稻叶尖枯病能够进行再侵染。

The results of study indicated that the primary inocula of rice Phyllosticta leaf blight (Phyllosticta oryzicola Hara) were associated with the diseased rice leaves, rice seeds, and field grasses. In diseased-area, the diseased leaves in the field were the main primary inocula. The percentage of diseased seeds was generally 0. 5~2. 5%, and the infected part was almost only in or on glumes. The grasses such as Echinochloa crusgalli var. mitts, E. crus-galli var. zelayensis, Paspaium distichum, Setaria viridis, Leersia japonica, Leptochloa chinensis, Eleusine indica , Chloris virgata , Imperata cylindrica , Zizama caduciflora , Dig-itaria sanguinalis, Arundo donas, and Cyperus sp. are also the hosts of P. oryzicola. Furthermore, the experiment showed that the secondary infection of P. oryzicola occurred in the field.