Management of Sugarcane Smut Disease using Triazole Fungicides and Synthetic Elicitors

Abstract

Sugarcane smut caused by <em>Sporisorium scitamineum </em>is a devastating disease of sugarcane. As a management strategy, seed sets of resistant varieties treat with fungicides after the hot water treatment. As a novel management strategy, we evaluated the possibility of using low concentrations of fungicides and synthetic elicitors under in vitro and field conditions. Three fungicides (i.e. Tebuconazole, Hexaconazole, and Metalaxyl 8 % + Mancozeb 64 % WP) and two synthetic elicitors (i.e. salicylic acid (SA) and jasmonic acid (JA)) were tested in vitro at four concentrations (i.e. 250, 500, 750, and 1000 ppm) for their efficacy on inhibition of the germination of smut teliospores. Tebuconazole, Hexaconazole, and salicylic acids completely inhibited the germination of the teliospores at 500 ppm, 250 ppm, and 750 ppm concentrations, respectively. Metalaxyl 8 % + Mancozeb 64 % WP and JA inhibited the teliospore germination by 52 and 58 % respectively at 1000 ppm concentration. In the field evaluation, smut pathogen was artificially inoculated to the seed sets of a resistant (Co 775) and a susceptible variety (SL 88 116) treated with fungicides and SA at selected concentrations. Disease incidence (DI) was recorded, and disease severity (DS), Area Under Disease Progress Curve (AUDPC), and Percentage Reduction of the Disease (PRD) were calculated. Tebuconazole 500 ppm, Hexaconazole 250 ppm, Hexaconazole 500 ppm, and salicylic Acid 1000 ppm successfully controlled the disease significantly(P=0.05) in terms of DI, DS, AUDPC, and PRD, hence can be used as a dip treatment of seed sets to control sugarcane smut disease.