Phytosanitary surveillance and characterization of the orange rust disease of sugarcane in Cuba

Abstract

Introduction. This work presents the research results obtained from the detection of orange rust in Cuba. With the objectives of to detect the presence of Puccinia kuehnii (W. Kruger) E. J. Butler; to evaluate the severity of the disease; to characterize the symptoms and response of cultivars to the pathogen; to determine a favorable time of the year for its development; to update its distribution in the country. Methods. Phytosanitary evaluations and diagnosis were carried out using optical microscopy and Real Time PCR, in commercial plantations, seed areas and experimental stations. Results. P. kuehnii was detected and reported for the first time in 2008. The highest severity was observed in CSR81-86, CSG398-92 and B52107, less in the positive controls CP72-2086 and Q124. Significant variations were observed between infected cultivars and that leaf +3 can be used in the severity evaluation. C01-227 was used as a susceptibility control and a protocol was elaborated to select resistant cultivars; the reaction of eight commercial cultivars was determined. P. kuehnii was detected in all the provinces; the highest number of infected genotypes is found in the areas of the experimental stations, mainly in Mayabeque, Villa Clara and Camagüey. As some conclusions the distribution of orange rust is classified as low prevalence. The results of the phytosanitary surveillance indicate that some of the main commercial cultivars are susceptible and confirm the potential danger of this disease, which is more severe in the plantations carried out from April to September.