Efficacy of Tebuconazole Against Rhizocfonia solani, Causal Agent of Rice Sheath Blight

Studies on the efficacy of tebuconazole in controlling the sheath blight pathogen, Rhizoctonia solani Kuhn were carried out both under laboratory and at field levels. In vitro studies with nine commercial fungicides indicated that the radial growth of R. solani was completely inhibited by propiconazole (Tilt), tebuconazole (Folicur), hexaconazole (Contaf) and carbendazim + mancozeb (Companion) at their recommended dosages. The fungicides viz., tricyclazole + propiconazole (Filia) and validamycin (Sheathmar) were equally effective with 97.8% and 95.4% growth inhibition of the test pathogen. Mancozeb (Indofil M-45) was also effective in reducing the mycelial growth of R. solani. Further, in vitro studies revealed that tebuconazole had inhibited the sclerotial germination when dipped in fungicidal solutions (at specified dosage) for a period of 5 minutes and above. None of the other fungicides could inhibit the germination of R. solani sclerotia even after a dip of 15 minutes in the fungicidal solution. Tebuconazole when applied at 1500 ppm was highly effective in the field in reducing the disease in rice and is on par with the standard fungicides viz., propiconazole and hexaconazole. The yield levels in tebuconazole (@1500 ppm) treated plots (3288 kg ha−1) were superior and were statistically at par with hexaconazole and propiconazole treatments.