BIOLOGICAL SUPPRESSION OF SUGARCANE RED ROT BY BACILLUS spp. UNDER FIELD CONDITIONS

Yield of sugarcane (Saccharum officinarum L.) is critically limited by the red rot disease caused by Colletotrichum falcatum Went. Four native antagonistic bacteria Bacillus subtilis strains NH-100, B. subtilis NH-160, Bacillus sp. NH-217 and NH-69, that successfully suppressed the red rot disease under greenhouse conditions were evaluated to determine their efficacy as biological control agents in the field. Performance of the antagonistic strains was assessed on two different sugarcane varieties SPF-234 and Co-1148 under field conditions for three consecutive years. Two types of trials were conducted in which the red rot pathogen was inoculated by different methods to observe its direct suppression as well as the induction of systemic resistance. Three strains of the genus Bacillus reduced disease incidence by 45-49% in sugarcane plants challenged by pathogen inoculation in the stem and by 48-56% in the plants inoculated in the soil near the roots. The results of present study suggest a potential use of these strains in the development of commercial inoculants to be applied for the control of red rot disease.