Leaf scald (Xanthomonas albilineans) is one of the major diseases of sugarcane due to the damage it causes and to its difficult identification, especially when the plant, although infected, does not exhibit visible symptoms (latent phase of the disease). This feature allows the occurrence of its dissemination to new areas through the planting of apparently healthy bud setts. Yield losses occur when plants, under water stress condition, exhibit chronic or acute symptoms of the disease. As the majority of commercial varieties currently grown in Brazil are asymptomatic carriers of the disease, correct diagnosis constitutes one of the main measures for successful control. The present study aimed to examine the efficiency of different diagnostic methods for X. albilineans. The obtained data demonstrated that the classic method for the pathogen isolation in culture media from the sap of the culm internodes was not reliable, whereas the amplification method by PCR detected the bacterium in plants with the three different symptoms of the disease.
Diagnosis; latent symptoms; DNA; PCR; Saccharum
