Integrated Disease Management of Banded Leaf and Sheath Blight of Maize Caused by Rhizoctonia solani

The experiments were carried out at the Department of Plant Pathology, Yezin Agricultural University from May 2014 to March 2015. The study was aimed to evaluate the pathogenicity of different isolates of Rhizoctonia solani, to determine the antagonistic effect of Trichoderma spp. on Rhizoctonia solani and to evaluate the effect of integrated disease management practices on banded leaf and sheath blight of maize. The pathogenicity of seven isolates of Rhizoctonia solani collected from Tatkone, Pyinmana, Lewe and Kyaukme were evaluated on three hybrid maize varieties, Yezin-10, Yezin-11 and CPDK-888. Out of the seven isolates of R. solani, Pyinmana isolate was found to be the most virulent one as it caused the highest disease severity on all test varieties. Among the three test varieties, CPDK-888 was found to be the most susceptible variety as it gave maximum disease severity for all test isolates. Four Trichoderma spp. namely, Trichoderma-1, Trichoderma-2, Trichoderma-3 and Trichoderma-4 from maize rhizospheric soil and a commercial Trichoderma harzianum were tested for their antagonistic effect on high virulent R. solani, Pyinmana isolate. In in vitro dual culture test, the Trichoderma spp., Trichoderma-1, Trichoderma-3 and Trichoderma-4 exhibited excellent inhibitory effects resulting in 91-97% inhibition on mycelial growth of R. solani at 4 days after incubation. In in vivo test, the highest percent disease control of 76% was obtained from the plants treated with Trichoderma-4 at 30 days after sowing of CPDK-888 variety. Out of single and integrated control measures, all were observed to be effective in reducing disease severity and increasing yield over untreated check. All disease control measures were applied up to four times for each treatment except stripping alone which was done up to two times before flowering. Among them, integrated control measures were found to be more effective resulting in 60.7-78.6% disease reduction than single control measure except Carbendazim alone showing 70% in disease reduction. By the economic analysis, higher cost and benefit ratios (C:B) were obtained from the plants treated with Trichoderma alone, Carbendazim alone and combination of Trichoderma and Carbendazim alternately against the disease. Therefore, based on these findings, alternate sprayings of Trichoderma and Carbendazim could be applied as the most suitable method in terms of economic and environmental aspects to control banded leaf and sheath blight of maize