Effect of bioagents on the growth of rice against blast disease caused by Pyricularia oryzae

Abstract

Rice (Oryza sativa L.) is the most important sources of food which provide diet more than 50% of the world population. Blast disease caused by Pyricularia oryzae, contributes a major reduction in rice production. The rampant use of fungicides causes deleterious effect on the environment. To minimise side effects of fungicides alternative means are opted. To concern about climate change, environment pollution and sustainable crop production disease management on sustainable basis is crucial. Thus, bioagents use as an alternative to chemical fungicides for the management of diseases. Effect of bio control agents (BCAs) evaluated against pathogen Pyricularia oryzae causing blast disease of rice in vitro and field condition. The result revealed that after three days of inoculation Trichoderma harzianum found most effective against Pyricularia oryzae which inhibited mycelial growth around 63%. Meanwhile Trichoderma viride inhibited 60% radial growth of Pyricularia oryzae. The best result shown by Trichoderma harzianum which inhibited pathogen by 63%, 56% and 41% at consecutive interval of three, five and seven days respectively. Dry shoot weight was found increased by T. harzianum (48.24%) followed by T. viride (45.98%) with respect to seed treated with pathogen. Among treatment of different bioagents the best yield was found 15.01 q/hac and 14.88 q/hac treatment with T. harzianum and T. viride against crop infected with pathogen. Seed treated with T. harzianum and T. viride the disease severity was found decreasing of 51.33% and 48.52% respectively. The application of bio control agents not only reduced the disease severity, promoted the plant growth and ultimately increased the grain yield significantly compared to control without any hazardous effect on environment.