Sclerotinia sclerotiorum. [Descriptions of Fungi and Bacteria].

A description is provided for Sclerotinia sclerotiorum. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: The fungus is plurivorous; hosts include Brassica oleracea var. capitata, B. chinensis, Helianthus annuus, Phaseolus vulgaris, Arachis hypogaea, Carthamus tinctorius, Citrus, Coriandrum sativum, Cucumis melo, Curcurbita pepo, Glycine max, Lycopersicon esculentum, Nicotiana tabacum, Lactuca saliva, Hibiscus sabdariffa, Cucumis sativus. DISEASE: The fungus causes dieases with several common names, e.g. cottony soft rot, white mould and watery soft rot. It is generally more important as a pathogen of vegetables in the field, during transit and in store. Woody plants, grasses and cereals are rarely attacked. Crops attacked include: cabbage (Brassica oleracea var. capitata and B. chinensis; 4, 713; 37, 611; 39, 515; 51, 2958); sunflower (Helianthus annuus; 3, 274; 4, 289; 8, 246; 38, 9; 43, 2012; 50, 3095; 51, 3486; 54, 4600; 55, 2832); common bean (Phaseolus vulgaris; 1, 116; 25, 592; 33, 401; 34, 425; 40, 446; 51, 870; 52, 531; 53, 731, 2373, 4183; 54, 4252, 4694; 55, 970); groundnut (Arachis hypogaea; 53, 3708); safflower (Carthamus tinctorius; 3, 650); citrus (Citrus spp. ; 24, 500; 43, 2910); coriander (Coriandrum sativum; 43, 2373); melon (Cucumis melo; 50, 1543; 53, 1109); squash (Curcurbitapepo; 50, 446); soyabean (Glycine max; 52, 3485; 53, 335, 336) tomato (Lycopersicon esculentum; 33, 56); tobacco (Nicotiana tabacum; 12, 729; 14, 126; 38, 279; 39, 46; 55, 2355); lettuce (Lactuca saliva; 16, 13); roselle (Hibiscus sabdariffa; 14, 106); cucumber (Cucumis sativus; 55, 2953). Most plant parts, above and at soil level, of herbaceous crops can be attacked at any age. The first symptoms are frequently the collapse of the plant due to stem infection near the soil. A soft rot develops, followed by the conspicuous, external white mycelium and the sclerotia which are often formed in the pith. Infections which arise at some height above soil level frequently begin from withering or fallen petals, infected by ascospores. GEOGRAPHICAL DISTRIBUTION: Very widespread but the disease is one of relatively cool moist conditions. In the Mediterranean area little or no disease occurs in the summer (31, 250; 43, 14). TRANSMISSION: Air-borne ascospores are the most important means of spread (12, 193; 33, 56, 401; 37, 611; 42, 527; 54, 4252, 4694; 55, 442, 970). The sclerotia (from which the apothecia arise) are the primary survival structures, in soil and host debris. Survival time is very variable but can be high after 3 years in soil (42, 244; 43, 2756; 45, 818; 50, 1621; 52, 3956; 54, 3712, 4252; Hoes, Phytopathology 65: 1431, 1975). Mycelium from sclerotia can also cause infection. Seed may be an infective source, either from contaminating sclerotia or internal mycelium (38, 169; 43, 1376; 47, 1998; 51, 3487; 52, 3485; 53, 335, 336).