Fusarium wilt

It is a fungal disease. Symptoms include partial or total wilting of plants at flowering and podding, a purple band of stems extending from the base upwards, browning of the stem tissue in the purple band area, and browning or blackening of internal tissue when the main stem or primary branches are split. Infected young plants may not show the purple band symptom but have conspicuous internal browning and blackening. Affected fields show patches of dead plants. The fungus survives on infected crop debris in the soil for about three years. Infection occurs from seeds or soil. Non-opening varieties are not as susceptible.