Further Developments in the Study of the Ratoon Stunting Disease of Sugarcane in Puerto Rico

Abstract

Small, coryneform, noncultivable xylem-inhabitating bacteria with mesosomes, measuring 1430-1830 nm x 140-165 nm, were observed in negatively stained juice extracted from sugarcane varieties B 49-11 9, PR 1059 and PR 1140, showing internal symptoms of ratoon stunting disease. Ten sugarcane varieties, PR 1059, PR 1140, PR 61-902, PR 62-258, PR 62-285, PR 64-15, PR 64-610, B 49-119, CB 49-260 and CP 52-43, were tested for resistance to ratoon stunting disease. PR 61-902, inoculated with the causal agent, produced significantly less cane and sugar per acre (approximately 31%) in plant cane, first ratoon and second ratoon crops as compared with those obtained from disease-free, hot water treated nursery stock. Therefore, it is recommendable to use only the ratoon stunting disease-free seed pieces of this variety for commercial planting in Puerto Rico.