The biology ofSclerotinia sclerotiorum,S. trifoliorum,andS. minor with emphasis on specific nomenclature

The separation ofSclerotinia sclerotiorum (Lib.) de Bary, 5.trifoliorum Erikss., andS. minor Jagger into three distinct species has been based on traditional morphological and physiological criteria such as gross cultural characteristics, sclerotial size, ascus and ascospore dimensions, time of apothecial development in the field, and host association. However, these characteristics tend to be variable and some workers have concluded that the three fungi should be included in one species, 5.sclerotiorum. Recently, new data have been published on morphological, cultural, physiological, ontogenetic, enzyme pattern, mycelial interaction, and cytological characteristics of isolates ofSclerotinia spp. This information supplements, but does not replace, that available from more traditional taxonomic methods and helps to resolve the controversy on the taxonomy and nomenclature of these fungi. This article reviews the relevant literature on the biology of 5.sclerotiorum, S. trifoliorum, and 5.minor, with particular emphasis given to those differences between them that could be of significance regarding their specific nomenclature. After an introduction, mycelia, microconidia, sclerotia, apothecia, infection, control, and taxonomy and nomenclature are discussed. The authors conclude thatS. sclerotiorum, S. trifoliorum, andS. minor are distinct species. The characteristics used to distinguish between them are summarized in table form.