Epidemiological factors influencing Alternaria blight severity of clusterbean in northern Madhya Pradesh

Abstract

Alternaria blight caused by Alternaria cyamopsidis is a serious foliar disease of clusterbean responsible for substantial yield losses under favorable environmental conditions. A field investigation was conducted during Kharif 2021 and 2022 in Northern Madhya Pradesh to study epidemiological aspects influencing disease development. Disease severity was assessed in relation to environmental conditions across Gwalior, Morena, and Shivpuri districts. Results indicated that disease severity increased during periods of high humidity, intermittent rainfall, and moderate temperature. Gwalior district recorded maximum disease severity during both years, while Shivpuri exhibited minimum disease incidence. The mean disease intensity increased from 17.96 percent in 2021 to 19.86 percent in 2022, indicating the influence of favorable weather conditions during 2022. Disease development was positively associated with prolonged leaf wetness and dense crop canopy. The study highlights the importance of epidemiological understanding for developing effective integrated disease management strategies against Alternaria blight of clusterbean.