Alternaria ricini. [Descriptions of Fungi and Bacteria].
Abstract A description is provided for Alternaria ricini. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Ricinus communis. DISEASE: Seedling blight, leaf spot, inflorescence and pod rot of castor. Leaf lesions are irregular in outline, variable in size but often quite large, brown, zonate, with a yellow halo. Defoliation can be extensive. The inflorescence is attacked at any age and eventually develops a sooty appearance as sporulation occurs under high humidity conditions. The capsules can wilt suddenly and become purple dark brown, the seed is poorly filled and may become infected; normal dehiscence fails. Alternatively a sunken area appears on one side of the capsule and eventually covers the whole of it, the seed is fairly well grown and dehiscence is normal. Seedlings which are infected have stunted cotyledons, become spotted and may be killed. GEOGRAPHICAL DISTRIBUTION: Occurs in E. & W. Africa, S. Asia and S. & E. U.S.A., see CMI Map 345, ed. 2; one additional record is Angola. TRANSMISSION: Seed-borne. Infected capsules can give rise to seed which may have the coat, caruncle or endosperm infected. Seeds from such capsules give diseased seedlings. Seed dressings did not completely control the disease (39: 211).