Soil transmission of the ratoon stunting disease bacterium Clavibacter xyli subsp. xyli
| MSI99P0101 | |
| Autrey, L. J. C. Dookun, A. Saumtally, S. Dhayan, S. Sullivan, S. | |
| Soil transmission of the ratoon stunting disease bacterium Clavibacter xyli subsp. xyli | |
| 3rd ISSCT Sugar Cane Pathology Workshop, MSIRI, Reduit, 22-26 July 1991 | |
| Conference paper | |
| 1991 | |
| En | |
| En | |
| Two trials were established under highly contrasting environments in the dry and superhumid zones to study the effects of the ratoon stunting disease (RSD) organism, Clavibacter xyli subsp. xyli, on yield in variety M574.62. Despite all sanitary measures taken, the bacterium was found in plots established with disease-free material. The level of infection in plant canes was low, i.e. 5 per cent. In ratoons the level of infection rose in all plots of the trials, especially in the one located in the superhumid zone where differences in yield due to the disease became practically non-significant. Owing to an exceptional drought, the differences in yield were maintained between plots issuing from healthy and diseased material in the trial in the dry zone. Aerial transmission through guttation droplets and transpiration stream was not evident although the RSD bacterium could easily be detected in leaf juice. Transmission of the organism through the soil was suspected to be the factor accounting for the results obtained in the trial in the superhumid zone. Two glasshouse trials were initiated to verify this hypothesis. In the first trials 25 ml of a bacterial suspension of 1 x 10 9 cells/ml of C. xyli subsp. xyli were mixed with sterilized soil contained in two-litre polyethylene pots in which cuttings of variety M574/62 issuing stalks showed abundant RSD infection. Controls consisting of uninoculated sterile soil and placed at random among inoculated pots were free from the bacterium. In a second trial the following treatments were investigated in trays of sterilized soil with variety M574/62: (1) One row of 5 diseased cuttings sandwiched between two rows of 5 healthy cuttings; (2) One row of healthy cuttings sandwiched between tow rows of 5 diseases cuttings; (3) Three rows of alternate healthy and diseased cuttings. Control trays consisted of healthy and diseased cuttings planted separately in the same soil as the other treatments. The trays were placed at random in the open glasshouse. After 10 months, all stalks in treatments 1, 2 and 3 were found to be highly infected with the bacterium as well as those in the tray established with diseased cuttings only. No RSD was recovered from the control consisting of healthy cuttings. It is inferred that the RSD bacterium can be transmitted from diseaed to healthy cuttings either by root contact or through the soil. As the bacterium was observed from the soil using both phase-contrast microscopy and indirect immunofluorescence, it is thought that root to root contact is not necessary for transmission. Trials are under way in the glasshouse and in the field to confirm the viability of the bacteria in soil and its transmission to tealthy cuttings. | |
| SUGARCANE BACTERIAL DISEASES TRANSMISSION DISEASES RATOON STUNTING DISEASE CLAVIBACTER XYLI RSD | |
| MAURITIUS | |
| Sugarcane: Diseases and disease management | |
| Bacterial diseases: Ratoon Stunting Disease | |
| 1992-01-21 | |
| En | |
| Mauritius Sugar Industry Research Institute | |
| LIB | |
| CAT | |
| PATH |