Efficacy of different fungicides against the in-vitro growth of Pyricularia oryzae causing Rice blast disease

Abstract

Rice blast disease caused by Pyricularia oryzae is a major threat to the farmers as the disease severity may lead upto 80% crop loss in severe conditions. A laboratory experiment was conducted at National Plant Pathology Research center of NARC, Khumaltar,Lalitpur for testing the efficacy of different fungicides adopting poisoned food method against the pathogen Pyricularia oryzae causing rice blast disease. The experiment was carried out in a completely randomized design with 10 treatments including control following 3 replications of each. Two concentrations (50 ppm and 100 ppm) each of different fungicides viz. Dithane M-45 (Mancozeb 75%W.P), Bavistin (Carbendazim 50 % W.P), Antracol (Propineb 70%W.P) , Diamethmorph 50%WP, Sectin ( Fenamidone 10%+ Mancozeb 50%W.G),Protector ZN ( Chlorothalonil 75% W.P), Safaya (Carbendazim 12%+ mancozeb63% W.P) , Nativo 75% W.G (Tebuconazole 50%+ Trifloxystrobin25%W.G) and Topcare ( Azoxystrobin 50% W.D.G) were evaluated against the growth of the pathogen. Results showed that lower concentration (50ppm) of Bavistin and Safaya fully inhibited the growth of the pathogen while Nativo at higher concentration (100 ppm) was shown to exhibit 100% inhibition of the pathogen. The fungicides significantly inhibited the mycelia growth with the increase in concentration of fungicide. However, the fungicides found effective for mycelia inhibition of P.oryzae should be further tested in field conditions to verify their efficacy as well the optimum dozes of fungicide should be re-evaluated.