African maize stalk borer

Taxonomic position. The African maize stalk borer (Busseola fusca) belongs to the order Lepidoptera, family Noctuidae. It is widely recognized as one of the most devastating pests of cereal crops across sub-Saharan Africa, posing a constant threat to food security.

Host crops and damage. The primary hosts include maize and sorghum, although it occasionally attacks sugarcane and various wild grasses. The economic impact is severe as the larvae bore into the stems, destroying the plant's vascular tissue and preventing normal nutrient transport, often resulting in complete yield failure.

Biology and life cycle. The life cycle comprises egg, larval, pupal, and adult stages. Females lay eggs under leaf sheaths. Upon hatching, larvae initially feed on tender leaf tissue before tunneling into the stem. Depending on regional temperatures and humidity, multiple generations can occur within a single cropping season.

Nature of injury. Early signs include "windowing" on leaves where the epidermis remains intact. As the larvae grow, they migrate deep into the stalks, creating internal galleries. This internal feeding often causes "dead heart" symptoms, where the central leaf withers and dies, leading to stunted plants or entire crop collapse.

• Cultural practices such as crop rotation with non-host plants.
• Destruction of crop residues to eliminate overwintering sites.
• Planting of resistant or genetically modified maize hybrids.
• Application of microbial insecticides based on Bacillus thuringiensis.
• Regular field monitoring and timely chemical application during the peak egg-laying phase.