Bio-efficacy of fungicides for management of blast disease caused by Pyricularia oryzae Cavara in rice

Abstract

Blast disease caused by Pyricularia oryzae Cavara [synonym Pyricularia grisea Sacc. the anamorph Magnaporthe grisea (Herbert) Yaegashi and Udagawa], is an important disease of rice. For effective management of blast disease of rice through fungicides a field trial was conducted during kharif 2015 at Regional Agricultural Research Station, Shillongani, Nagaon - 782002, Assam. Of the 7(seven) fungicides tested, trifloxystrobin 25% + tebuconazole 50% w/w (Nativo 75 WG) @ 0.04% recorded lowest PDI of leaf blast 3.9% followed by tricyclazole 75 WP @ 0.06% with PDI 6.16% were statistically at par. Further, neck blast incidence in two fungicides namely, trifloxystrobin 25% + tebuconazole 50% w/w @ 0.04% and tricyclazole 75 WP @ 0.06% recorded 4.53 per cent and 4.7 per cent were found statistically at par, whereas yield recorded 3.57 t/ha and 3.30 t/ha with an increased yield 90.91% and 76.48% over the control were also statistically at par with BC ratio 1.73 and 1.74 respectively. Besides, neck blast incidence and yield recorded in fungicide carbendazim 50 WP were found statistically at par with Nativo 75 WG and tricyclazole 75 WP with highest BC ratio 1.75. These three fungicides namely, Nativo 75 WG, Tricyclazole 75 WP and Carbendazim 50 WP may rotate to reduce the chances of new strain development of the fungus Pyricularia oryzae in rice cultivation.