African cassava mosaic

African cassava mosaic is a viral disease caused by a complex of viruses within the genus Begomovirus, family Geminiviridae. This pathogen is one of the most destructive factors limiting cassava production, posing a serious threat to food security in affected tropical regions.

The primary host plant is cassava (Manihot esculenta), a vital subsistence crop. The virus affects the entire plant systemically, colonizing the phloem and interfering with normal nutrient transport and metabolic processes, ultimately leading to significant yield losses.

The most common visual symptoms include mosaic patterns on leaves, yellowing (chlorosis), leaf distortion, and severe stunting of the entire plant. In infected plants, the reduction of leaf surface area directly correlates with decreased carbohydrate production in the tubers.

The transmission of the virus occurs primarily through the silverleaf whitefly (Bemisia tabaci), which acts as a vector. Environmental conditions such as elevated temperatures and drought stress can enhance the movement of whiteflies and the subsequent spread of the virus across neighboring plots.

Management strategies focus on integrated pest management (IPM) practices to mitigate the impact of the disease. Key interventions include:

• Propagation using virus-free cuttings or tissue-cultured plantlets.
• Breeding and cultivation of mosaic-resistant cassava varieties.
• Strict field sanitation through the rogueing of symptomatic plants.
• Monitoring and management of whitefly populations to break the infection cycle.