Field assessment of cultivar mixtures for managing finger millet blast (Pyricularia grisea) using disease progress curves

The performance of cultivar mixtures under field conditions is pivotal for managing plant diseases, especially in mitigating air-borne pathogen epidemics in millets. This study evaluates the impact of various mixed-culture combinations on blast epidemics in finger millet, with a focus on ensuring yield stability. Disease progress curves for leaf, neck and finger blast were monitored at regular intervals. Repeated disease assessments were crucial for calculating the Area Under the Disease Progress Curve (AUDPC), a key indicator used to quantify the level of resistance to blast disease. Treatments included combinations of commercial variety and pre-released cultures paired with a resistant cultivar in different ratios (2:1 and 1:1) to curtail finger millet blast disease. Their effectiveness was equated with chemical/fungicide treatment. The pre-released cultures and resistant cultivar combination in a 1:1 share proved highly effective, significantly reducing the AUDPC values for leaf, neck and finger blasts whereas delivering sustainable outcomes. The cultivar mixture management practice performed comparably to chemical applications (Tricyclazole 75 % WP) during the 2020 and 2021 growing seasons. This cultural composite, delayed disease onset and slowed its progression during epidemics. The mixed-culture approach consistently achieved sustainable yields across trials while reducing the need for fungicidal applications.