Prevalence and distribution of rice blast disease in different rice ecosystems of Karnataka, India

Abstract

Rice is the most widely consumed cereal staple food for a significant part of the world, particularly in Asia. The Karnataka state of India is one of the highest rice producers, and it has a varied rice ecosystem from irrigated plains to rainfed hilly areas. The rice blast occurs at different severity in these ecosystems causing significant losses each year. The roving survey was carried out in the 120 villages of 18 districts distributed under five irrigated and two rainfed ecosystems of Karnataka during Kharif -2019. Within the irrigated ecosystems, the highest PDI was observed in the Kavery (50.85), followed by Varada (45.89), Bhadra (45.82), Tungabhadra (11.13), and Upper Krishna (10.58) command areas. In a rainfed ecosystem, the highest PDI was observed in the hilly ecosystem (53.38) and the least in the coastal ecosystem (3.73). Within 18 districts, the lowest PDI was observed in the Gadag district (1.68) of the Thungabhadra ecosystem, and the highest was observed in the Chikkamagalur district (81.60) of the hilly ecosystem. The disease was severe in the rainfed hilly ecosystem, followed by an irrigated and rainfed coastal ecosystem. This information is helpful in formulating the management strategies of rice blast in different rice ecosystems of Karnataka.