Cassava mosaic disease

Cassava mosaic disease (CMD) is a devastating viral infection caused by various species of geminiviruses. This disease is highly specific to the cassava plant (Manihot esculenta) and poses a major threat to food security in regions where cassava serves as a staple caloric source.

The primary symptoms include a characteristic mosaic pattern on the leaves, featuring irregular patches of yellow, light green, and dark green discoloration. The foliage often becomes distorted, stunted, and curled, which significantly interferes with the plant's photosynthetic capacity and overall health.

The virus is primarily transmitted through the use of infected cuttings during vegetative propagation, which is the standard practice for planting cassava. Additionally, the whitefly (Bemisia tabaci) acts as an efficient vector, spreading the virus rapidly between plants in a field during the growing season.

The impact of CMD on crop yields is severe, often resulting in losses ranging from 20% up to 90%. Infected plants fail to develop healthy storage roots, producing smaller tubers that lack the starch density required for high-quality yields, which directly impacts farm profitability.

Preventive and control measures are critical for managing the disease:

• sourcing and planting only virus-free, certified cuttings;
• deploying resistant or tolerant cassava cultivars;
• rigorous roguing (removal and destruction) of symptomatic plants;
• implementing integrated pest management to control whitefly populations.