Combined effect of Millet-Cowpea intercropping and biopesticide application against Heliocheilus albipunctella De Joannis (Lepidoptera: Noctuidae) in Burkina Faso.

Pearl millet, Pennisetum glaucum L. R. Br. (Poales: Poaceae), the main cereal crop in the Sahelian zone of Burkina Faso, is attacked by several insect pests, among which is the millet head miner, Heliocheilus albipunctella De Joannis (Lepidoptera: Noctuidae). Damage and yield losses caused by H. albipunctella on millet range from 30.00% to 85.00%. Control and management of H. albipunctella currently rely on synthetic insecticides, which are harmful to human and environmental health. Hence, there is a need to explore and develop alternative management strategies. Consequently, the current research, which was conducted, explored the use of millet-cowpea intercropping, a very common practice in the Sahelian zone of Burkina Faso, together with the application of biopesticides of Neem (Azadirachta indica A. Juss. (Sapindales: Meliaceae) seed kernels aqueous extracts. Fieldwork was carried out in Burkina Faso's Djibasso and Dori communes during the 2021 rainy period. The obtained results found that the application of Neem extracts on cowpea plants at the flowering stage, synchronized with the heading stage of millet, significantly reduced the incidence of H. albipunctella. When millet was intercropped with cowpea, the application of aqueous extracts of Neem indirectly led to a significant reduction of about 50.00% in the number of larvae per spike. Additionally, a reduction in the percentage of millet spikes attacked, a decrease in mine length, and a gain in grain yield of more than 40.00% were observed. Thus, the findings from the application of this agricultural practice could be a promising control option against H. albipunctella.