National Symposium on Strategic Issues in Plant Pathological Research held at Department of Plant Pathology, CSK HP Krishi Vishvavidayalaya, Palampur on November 24–25, 2011
Pyricularia grisea (Cooke) Sacc., the cause of rice blast, is one of the most important fungal pathogens of rice (Oryza sativa L.) because of its widespread occurrence and destructive nature. The disease has been causing yield losses in India ever since 1913. The fungus can attack any aerial part of the rice plant, including seeds, in which the fungus may overwinter for several years. In order to manage the disease, various fungicides, namely, Folicur (tebuconazole), Tilt (propiconazole), Score (difenconazole), Dithane-78 (zineb), Kasu-B (kasugamycin), Amistar top (azoxystrobin + difenconazole), Baan (tricyclazole) and Merger (tricyclazole + mancozeb) were screened under in vitro conditions each at a concentration of 0.1, 1, 10, 25, 50 and 100 ppm employing poisoned food technique using carrot extract agar as basal medium. Among the fungicides tested, Tilt, Amistar top, Score and Folicur were found significantly effective over other treatments. Tilt exhibited 100 per cent growth inhibition at 10 ppm while Folicur, Amistar top and Score exhibited 100 per cent growth inhibition at 25 ppm. Merger and Baan exhibited 50 per cent growth inhibition at 10 and 25 ppm respectively. However, Kasu-B registered the least (60 per cent) growth inhibition of fungal growth at 100 ppm. These studies revealed that Tilt followed by Amistar top, Score and Folicur are most promising fungicides and thus can be evaluated under field conditions for blast management.
