Septoria passifloricola. [Descriptions of Fungi and Bacteria].
Abstract A description is provided for Septoria passifloricola. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Passiflora brasiliensis (= P. alata), P. edulis, P. macrocarpa, P. quadrangularis, P. quitensis. DISEASE: Leaf, blossom, fruit and stem spot (22, 393; 35, 588). Leaves, blossoms, fruit skin and stems are all susceptible to attack. The visible symptoms on leaves are circular to irregular, light brown, sharply defined, necrotic lesions reaching 5-10 mm diam., surrounded by a yellowish zone. Severe attacks may result in premature drop of leaves and blossoms. On blossoms the disease lesions are somewhat similar to those on leaves, the primary infection of the calyx may extend to the stalks, resulting in the premature shedding of flowers. On the immature fruits more or less circular sharply demarcated brown spots tend to coalesce to form large irregular necrotic, somewhat depressed patches of a hard consistency. On the young stems, the lesions appear as small, irregularly circular to elongated water-soaked areas. When stems of young plants are affected, they may gradually become engirdled by a band of necrotic tissue, as a result of which young stems may wither and die (22, 393-394). GEOGRAPHICAL DISTRIBUTION: Africa (Ethiopia, Kenya, South Africa, Tanzania, Zambia); Australasia & Oceania (Australia, New Caledonia, New Zealand); Central America and West Indies (Trinidad); South America (Venezuela). TRANSMISSION: Rainfall and temperatures have been claimed to be decisive factors in the epidemiology and dissemination of the disease. Conidia within pycnidia on infected leaves stored under dry laboratory conditions were reported to show a reduction in their germinative capacity after three months. Conidia maintained under such conditions have been claimed to be non-viable after five months (Louw, 1941). It has been presumed that large amounts of pycnidia generated saprophytically on infected, prematurely dropped leaves trapped by the dense growth of the vines and protected from desiccation might have a significant effect on the initiation of epidemics.