ABSTRACT
Introduction Ratoon stunting disease (RSD), one of the most important diseases of sugarcane worldwide (Gillaspie and Teakle, 1989), is caused by a xylemlimiting bacterium Lei.fsonia xyli ssp. xyli (Lxx) (Syn. Clavibacter xyli ssp. xyll). The loss to sugarcane crop due to RSD varies, depending on varietal susceptibility and disease incidence. The disease causes considerable yield loss to sugarcane production in the USA, the African countries, Mauritius, Australia and in certain parts of Asia. In India, the presence of the disease was observed by Prof. Chilton, in the variety CoS 510 (Chona, 1956). Later, the presence of the disease was recorded in all the sugarcane-growing regions in India. Though the disease was recorded at different regions, its importance was overlooked due to other devastating diseases such as red rot (Colletotrichum falcatum Went), smut (Ustilago scitaminea Syd.) and wilt (Cephalosporium sacchari and Fusarium monilifvrmae). Several varieties such as Co 213, Co 312, Co 419, Co 453, Co 740, Co 975, Co 997, CoL 9, BO 22, etc., were reported to be inflicted with RSD in the past. Severity of RSD in southern Karnataka in India caused great yield loss in the popular variety Co 419. Many of the surveyed fields in these areas had 100 per cent disease incidence and such fields record only 50% of cane yield as compared to disease-free crop in other regions. Furthermore, the combined infection of RSD and yellow leaf syndrome (YLS) severely affects crop production (Vlswanathan, unpublished).
