Septoria leucanthemi. [Descriptions of Fungi and Bacteria].
Abstract A description is provided for Septoria leucanthemi. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: On Chrysanthemum leucanthemum, C. maximum, C. segetum. Also by inoculation on Chrysanthemum parthenium, C. roseum, Tagetes patula, Centaurea cyanus, Achillea ptarmica, Helichrysum sp., Helianthus annuus. DISEASE: Leaf spot of ox-eye daisy (Chrysanthemum leucanthemum[Leucanthemum vulgare]), shasta daisy (C. maximum) and corn marigold (C. segetum). The disease is sometimes referred to as leaf blotch of shasta daisy (Wormald, 1925). Symptoms appear on leaves of all ages and are of two types: dark brown circular or semicircular zonate lesions with a central sunken pale or whitish area surrounded by somewhat elevated concentric markings and measuring 0.5-2 cm wide; shot-hole spot usually appearing during extremely wet conditions, where the central pale depressed area falls off leaving behind spots with abundant pycnidia around the rim of the shot-hole. In severe cases leaves turn yellow and completely wither. GEOGRAPHICAL DISTRIBUTION: Africa (South Africa); Asia (U.S.S.R.); N. and S. America (Canada, U.S.A., Argentina); Europe (Denmark, France, Germany, Great Britain, Italy, Norway, Portugal, Spain, Yugoslavia. (Literature; Herb. IMI). TRANSMISSION: The pathogen may be transmitted by splashing rain drops and by contact. It remains in a viable condition in diseased plant debris and serves as the inoculum for the following year.