Abstract
A description is provided for Clavibacter XYLI subsp. XYLI. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOST: Saccharum officinarum, where it is restricted to the xylem. It produces a characteristic wilting when inoculated into sorghum-Sudan grass hybrid NB280S (61, 5933); also able to multiply in the xylem of various grasses and cereals, including Brachiaria mutica, B. miliiformis, Chloris gayana, Cynodon dactylon, Echinochloa colonum, Imperata cylindrica, Panicum maximum, Pennisetum purpureum, Rhynchelytrum repens, Sorghum bicolor, S. halepense, S. sudanense, S. verticilliporum, Sporobolus capensis and Zea mays when artificially inoculated, but although it can be transmitted back to sugar cane to produce the disease, it does not produce symptoms in these plants (Gillespie & Teakle, 1989). DISEASE: Ratoon stunting disease (RSD) of sugar cane. The cane makes slower than normal growth and is generally unthrifty. Canes are thinner with shorter internodes than normal and ratoon or stubble crops are particularly affected. Internally, reddish vascular bundles may be seen, especially at the nodes, or in immature cane, the interior of the nodes may be generally a faint pink. Such symptoms are, however, not particularly reliable for diagnosis, as they can result from stress caused by other factors. To confirm the disease it is probably best to observe the bacterium in the vessels by light or electron microscopy, use a serological method or both. GEOGRAPHICAL DISTRIBUTION: Very widespread due to transmission in planting material. Records include: Burkina Faso, Cameroon, Congo, Egypt, Ethiopia, Kenya, Madagascar, Malawi, Mali, Mauritius, Mozambique, Nigeria, Reunion, South Africa (Natal), Sudan, Swaziland, Tanzania, Uganda, Zaire, Zimbabwe, Bangladesh, Burma, China, India (Madhya Pradesh, Karnataka, Punjab, Uttar Pradesh), Indonesia (Java), Japan, Malaysia (W.), Philippines, Sri Lanka, Taiwan, Thailand, Australia (NSW, Qd), Fiji, Hawaii, Spain, Mexico, USA (Florida, LA), Antigua, Barbados, Belize, Cuba, Dominican Republic, Jamaica, Nevis, Nicaragua, Panama, Puerto Rico, El Salvador, St. Kitts, Trinidad, Argentina, Brazil (Rio de Janeiro), Colombia, Guyana, Peru, Uruguay, Venezuela (IMI Distribution Map 318, ed. 4, 1982; 63, 2478; 64, 2151; 66, 2051; 69, 5165; ISSCT List 1983). TRANSMISSION: To new areas in vegetative planting material and within the crop by mechanical means such as cutting knives and mechanical harvesters. Rats may also spread the disease.
