Sphaeropsis tumefaciens. [Descriptions of Fungi and Bacteria].
Abstract A description is provided for Sphaeropsis tumefaciens. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: On Citrus aurantifolia and other species of Citrus (sweet orange, rough lemon and ortanique). DISEASES: Knot of lime (Citrus aurantifolia) and other species of Citrus including sweet orange, rough lemon and ortanique. The so-called knots are gall-like growths, rounded (1-7 cm diam.) but sometimes elongated, on the stems. These swellings begin by being covered with normal bark which changes to a whitish, rough, cork-like tissue, this extends in size, becoming fissured, with mueh enlarged woody tissue. The knots are firmly attached and may occur in large numbers over considerable lengths of stem which may be girdled and killed. The surface of the knot may become soft and crumbling, but it is hard inside, where black streaking indicates the presence of mycelium. A gall may form up to 40 shoots, from multiple bud formation, some over 1 m long and often themselves bearing knots or galls (witches' broom effect). These abnormal shoots eventually die. Knots can occur on the trunk and severe infection leads to death of the tree. GEOGRAPHICAL DISTRIBUTION: Possible confusion with other similar disease-like symptoms in citrus (and because considerable damage only seems to occur in Jamaica) makes the distribution uncertain (CMI Map 386. ed. 1, 1961). Besides Jamaica it occurs in Florida and has been described from Cameroon (27: 564) and India (40: 533); it has also been reported from Ceylon, Cuba, Egypt, Guyana, Indonesia (Java), Venezuela. Some of these records are considered to be doubtful. TRANSMISSION: Not known.