Assessment of Plant Extracts Against Colletotrichum falcatum Causing Red Rot of Sugarcane

Abstract

Red rot of sugarcane caused by Colletotrichum falcatum Went.  is considered a major disease as it affects the  stalks which are economically important and causing a significant reduction in both yield quantity and quality. Recommending commercial varieties resistant to red rot is one of the management method but extensive cultivation of a single variety over large areas led to extensive crop damages leads to epidemics. In addition, synthetic fungicides may also be used to control the disease but are harmful to human health and environment. Considering environmental sustainability, a study was conducted to evaluate the efficacy of plant leaf extracts  against red rot. In this study to evaluate the effectiveness of five plant leaf extracts viz., Nicotinia tabaccum (Tobacco), Zingiber officinale (Ginger), Curcuma longa (Turmeric), Eucalyptus spp (Eucalyptus) and Pongamia pinnata (Pongamia) against Colletotrichum falcatum CF06 in vitro using poisoned food assay and in vivo in micro plots. All tested plant extracts significantly inhibited the mycelial growth of C. falcatum in vitro compared to the control.  The pooled mean of three years data revealed that all the plant extracts had shown significant superiority  in inhibiting the growth of red rot causing pathogen C.falcatum in vitro. Among all the plant extracts, Eucalyptus leaf extract had recorded significantly highest percent inhibition of pathogen with  100.0 per cent due to its fungicidal property. Where as invivo, per cent germination of setts (44.74 %) and number of settlings survived (45.22 %) also improved in Eucalyptus leaf extract treatment. The study indicated that  leaf extracts such as Eucalyptus and Pongamia  demonstrated strong antifungal properties even at lower concentrations. These extracts  are safe for human and environment besides improves soil fertility thus can be integrated with other disease management strategies for sustainable red rot control in sugarcane.