Causal Organism - Brown Spot

The brown spot fungus produces multiseptate (three or more septa) conidiophore, singly or in bundles (generally 17), up to 600 μm long, and 4-8 μm wide. Conidia are generally curved, boat or club-shaped, with 6 to 14 transverse septa or cross walls, 63-153 x 14-22 μm, and often with a minute, slightly protruding hilum (dot at the point of attachment to a conidiophore).

The fungus is seedborne and initial infection occurs on young seedlings. Stubbles of the previous crop and alternate hosts, such as grasses, can be sources of secondary inoculum. It can spread from plant to plant and in the field by airborne spores.