Damping-off diseases

Damping-off diseases are caused by various fungi. Seed may be attacked by one or more seed-borne or soil-borne pathogens prior to either germination or emergence. This usually occurs when conditions are not optimum for plant development, such as in poorly-drained, cold, wet soils, or in very dry, crusted soils. Sorghum seedlings are very delicate during the emergence period and are slow to establish a permanent root system. As a result, sorghum depends upon its primary, temporary root system for a period longer than many other crops. Under less than optimal growing conditions, this primary root system is extremely vulnerable to soil-borne pathogens. This is when damping-off in a field is most visible and damaging. Affected seedlings are unthrifty and may show yellowing, wilting and death of leaves. Roots of diseased plants may be discoloured (whitish grey to pinkish brown) and rotted.