Colletotrichum falcatum and Fusarium species induce symptoms of red rot in sugarcane in Brazil

Abstract

Red rot is an important disease of sugarcane, reported from the main producing countries of the crop. The main causal agent is Colletotrichum falcatum, which induces reddish internal stalk rot, resulting in loss of quality and quantity of sugars. While the occurrence of this disease has been reported in plantations in Brazil, the aetiology of the disease is not yet fully understood. We isolated and identified the fungi associated with sugarcane plants showing symptoms of red rot. Thirty isolates were recovered and grouped by morphology within the genera Colletotrichum and Fusarium. Based on phylogenetic analyses of DNA sequences from ITS, ACT, SOD, GAPDH, and EF-1α, eight isolates were identified as C. falcatum (n = 6) and C. plurivorum (n = 2). Twenty-two isolates belonged to the Fusarium fujikuroi species complex and were identified as F. sacchari (n = 8), F. proliferatum (n = 3), and F. madaense (n = 11). Coinfection with C. falcatum and Fusarium species were frequently observed. C. falcatum and Fusarium strains induced reddening of internal tissues and stalk rot in sugarcane plants, symptoms of red rot, while Fusarium species also induced symptoms of pokkah boeng. C. plurivorum, whose sexual stage was observed on the surface of stems, did not induce stalk rot or leaf symptoms. The results obtained in this study clarify the aetiological agents of red rot of sugarcane in Brazil. The conditions that lead to the development of specific symptoms of red rot or pokkah boeng are under investigation.