Abstract

Major rice growing areas of Jammu sub-tropics (Jammu, Samba and Kathua Districts) were surveyed to ascertain the status and distributions of brown spot of rice during 2011 to 2012. The disease was reported from all the areas with area under brown spot progress curve (AUBSPC) ranging between 3150 and 3560, 3025.00 and 3100, and 2921 and 31050 in Jammu, Kathua and Samba districts, respectively. Under laboratory conditions, seven fungicides (propiconazole, hexaconazole, tricyclazole, carbendazim, triadimefon, mancozeb and azoxystrobin) were tested at 50, 100, 150, 200 and 250 ppm. Out of different fungicides, propiconazole was most effective with maximum inhibition of 97% at 250 ppm concentration. Under field conditions, three rice varieties viz., Basmati-370, Jaya and PC-19 were used for testing different fungicides at 0.1% concentration during 2011 to 2012 and application of propiconazole significantly reduced the disease severity (69, 73 and 70) and increased the grain yield (19, 12 and 21) of all the varieties as compared to their respective controls. It was concluded that timely spray of propiconazole reduce the disease severity and thereby increase the yield of the rice.

Key words: Brown spot, Bipolaris oryzae, severity, fungicides, management.