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. F. udum is seed and soil-borne. The fungus survives on infected crop debris in the soil for about 3 years.

Crop rotation is advisable against diseases such as Fusarium wilt. Pigeon pea is generally grown in inter- and mixed-cropping systems in rotation with other crops, particularly cereals. However, since the fungus-causing agent of wilt of pigeon pea survives on deep-seated roots of the host, the success of rotation will depend upon the field sanitation (removal of affected plants with their roots). A 4-5-year rotation has been found to free the field completely of the wilt pathogen (causing fungal agent). However, in smallholder scenarios this is not practical due to land restriction. One-year breaks with either sorghum or fallow reduced wilt in the following pigeon pea crop from more than 50 to below 20%.

Pigeon pea rotation with tobacco has been recommended as a possible means of control because of the adverse effect of tobacco root exudates on the pathogen. For more information on  Fusarium wilt click here.