Submitted to: Current Trends in Sugarcane Pathology
Publication Type: Book / Chapter
Publication Acceptance Date: December 16, 1996
Publication Date: N/A
Interpretive Summary: This chapter reviews the literature and current research conducted on dry top rot, a disease of sugarcane of economic importance in Puerto Rico during the 1920s and 1930s that was recently identified in Florida. Dry top rot appears to be of minimal threat because of its restricted geographic distribution and low risk of escaping detection in quarantines. The disease merits an update because of its recent observation in Florida.
Technical Abstract: Dry top rot, caused by Ligniera vasculorum, was observed in Florida in 1991 prior to that it had been economically important in Puerto Rico during the 1920s and 1930s. Dry top rot symptoms of sugarcane occur in mature plants and include initial drying of the spindle leaf tips, subsequent drying of the upper leaves, reduced internodal growth of stalks, gradual stalk drying and eventual stalk death. The pathogen inhabits the vascular system of sugarcane plants. Heat treatment of infected stalks at 52 C for 45 minutes partially eliminated the pathogen resulting in a reduced incidence in plants that germinated from the treated stalks. Although natural infection occurred in plants grown in the field where the disease was present, tests using either invested soil from the field or macerated stalks of infected plants as an inoculum source failed to infect plants in greenhouse tests. Based on natural infection tests in the field sugarcane cultivars varied in their reaction to dry top rot with most cultivars being resistant. A heritability value (h2 = 0.47) was obtained from the regression of the progeny disease incidence on their mid-parent dry top rot incidence indicating resistant cultivars should be able to developed