Alternaria blight of cumin status and management in India: A review

Alternaria blight management in cumin

Abstract

Cumin (Cuminum cyminum L.) is one of the oldest and most economically significant seed spices, serving as a vital component of India’s spice exports and traditional agriculture. However, its productivity is increasingly constrained by Alternaria blight, predominantly caused by Alternaria burnsii, which can inflict yield losses of up to 80% in major cumin-growing regions each year. The disease commonly manifests after flowering under conditions of high humidity and moderate temperatures (around 18°C), producing dark brown necrotic lesions on leaves and stems. Affected plants exhibit drooping stem tips and shrivelled seeds with reduced viability, leading to severe yield decline. Alternaria blight is primarily seed-borne, facilitating the long-distance dissemination of the pathogen, while the fungus also persists saprophytically in soil and crop debris, with conidia capable of surviving for extended periods under warm and dry conditions. Over the past three decades, extensive research has been devoted to understanding its symptomatology, etiology, epidemiology, and predisposing environmental factors. This review consolidates existing knowledge on disease diagnosis, pathogen characterization through morphological and molecular tools, and advances in management practices. Integrated approaches encompassing cultural methods, host-plant resistance, bioagents, botanical formulations, and judicious fungicide use have demonstrated significant potential in mitigating Alternaria blight. A holistic Integrated Disease Management (IDM) framework, combining eco-friendly and resilient strategies, holds promise for sustaining cumin productivity and ensuring long-term disease suppression in changing agroclimatic environments.