Efficacy of botanicals and fungicides against Rhizoctonia solani inciting sheath blight disease on Rice (Oryza sativa L.)

Among the fungal diseases, sheath blight, caused by multinucleate Rhizoctoniasolani Kuhn (teleomorph: Thanatephorus cucumeris Donk), a ubiquitous pathogen, is an important fungal disease of rice ranking only after blast and often rivalling it. The potential losses due to sheath blight alone in India has been up to 51.3%. In this study an attempt was made to investigate the antifungal efficacy of botanicals viz., neem (Azadirachtaindica), tulsi (Ocimum sanctum), garlic (Allium sativum), onion (Allium cepa), ginger (Zingiberofficinale) and various fungicides namely mancozeb, propiconazole, hexaconazole, carbendazim, and copper oxychlorideagainst Rhizoctoniasolani in vitro by poison food technique. R. solani was allowed to grow at 5%, 10% concentrations of botanicals and at 200, 500, 1000ppm of fungicides amended potato dextrose agar (PDA) medium. The effect of botanicals and fungicides on mycelial growth inhibition was recorded after 36, 48 and 72 post hrs inoculation (phi). It was observed that bulb extract of Allium sativum and rhizome extract of Zingier officinal suppressed the mycelial growth (80.19 and 76.32, respectively) @ 10% followed by leaf extract of Azadirachtaindica (72.78 %) after 72 phi. Among the fungicides, the complete fungal growth inhibition was observed in propiconazole and carbendazim fungicides amended medium.