Culture of Puccinia melanocephala on Detached Leaves and Uprights of Sugarcane in Puerto Rico

Abstract

Sugarcane rust (Puccinia melanocephala) was cultured through its uredial and telial stages on detached leaves and uprights of 10 sugarcane cultivars in test tube, as well as in petri dish-benzimidazole, kinetin and nutrient solutions. The infection type, incubation period and severity of rust varied with cultivars and with age of the plant. Detached uprights in test tubes containing benzimidazole nutrient solution (5 ml of 25 p/m benzimidazole + 5 ml of nutrient solution) stayed green more than 30 days. Uredial and telial pustules developed better on detached uprights than on detached leaves. Rust developed better on detached leaves in test tube containing benzimidazole nutrient solution than on leaves in the petri dishes containing the same solution; there was less rust development on detached leaves from 6-month-old plants than on those from younger ones. More than 95% of the 90 cultivars inoculated with the detached upright technique, showed rust reactions corresponding with those observed under natural infection in the fields.