Zonate leaf spot of mulberry, with special reference to the life-cycle and taxonomy of causal fungus Gonatophragmium mori.

Abstract

The zonate leaf spot fungus newly found on mulberry, Morus alba, in Japan since 1978 was identified as Gonatophragmium mori (Sawada) Deighton (=Spondylocladium mori Sawada). Many new host plants, being 28 species belonging to 24 genera of 16 families, were recorded through the field surveys around mulberry plantations. In the overwintering experiments with naturally or artificially infected leaves on Morus, Vitis and Broussonetia, development of teleomorph, the perfect state was confirmed. Ascospores serve as the primary infection source in early summer. From the pathogenicity to Morus and Vitis with ascospores and conidia, and the identity of morphological characteristics of perithecial and anamorph, conidial states, the causal fungus was re-classified as Acrospermum viticola Ikata apud Ikata and Hitomi (1931) having the conidial state, Gonatophragmium mori (Sawada) Deighton (1969).