Assessment and management of diverse isolates of Colletotrichum falcatum associated with red rot disease in sugarcane

Abstract

Red rot, a devastating disease affecting sugarcane worldwide, is caused by the pathogen Colletotrichum falcatum. This menace poses a serious threat to sugarcane production, affecting all parts of the sugarcane plant, including leaves, midribs, and stalks. In our comprehensive study, we investigated the morphological, cultural, and pathogenic variability among isolates from midribs and stalks infected with the red rot pathogen. Our research revealed significant variations in mycelium growth among the three isolates from midribs and stalks. These isolates displayed distinct characteristics such as raised fluffy or flat white mycelium growth with light orange pigmentation and a medium to high level of sporulation. The conidia exhibited a falcate shape with an average size of 28.3 µm x 6.75 µm. Pathogenicity was assessed using both the pinprick and plug methods, both of which effectively evaluated disease severity in the CoJ 85 sugarcane variety. An epidemiological investigation highlighted the significant influence of relative humidity on disease development. To combat red rot, we evaluated seven different treatments. Among these, Bavistin, Trichoderma harzianum, and T. viride emerged as the most effective approaches. In addition to fungicides, biocontrol agents have shown promise in managing red rot by targeting C. falcatum and inducing systemic resistance in treated plants.