Tolerance and Susceptibility of Cowpea (Vigna unguiculata (L.) Walp.) Cultivars to Major Pathological and Entomological Pressures on Sub-Saharan Ferralsols
Cowpea is a grain legume, rich in proteins, carbohydrates, vitamins, and minerals. It enriches the soil through its biological nitrogen fixation capacity, thanks to rhizobia associated with its roots. Unfortunately, in sub-Saharan Africa, particularly in the Democratic Republic of Congo, within the territory of Tshilenge, the production of this crop faces biotic constraints. The most frequent diseases are anthracnose, cercosporiosis, and viral mosaic, as well as attacks by Anoplocnemis curvipes and Ootheca mutabilis. As a hypothesis for this study, we assume that certain cowpea cultivars would be tolerant while others would be susceptible to the major pathologies and pests in the Tshilenge region. The objective of this study is to identify the most tolerant and most susceptible cowpea cultivars to major pathological and pest pressures on sub-Saharan ferralsols in the Tshilenge region, Kasaï Oriental, through experimentation at different sowing dates. The results reveal that certain cultivars stand out for their remarkable tolerance, while others express increased susceptibility to major pathologies and pests. Cultivars C6 (index = 0), C1 (0.708), and C14 (0.744) are the most tolerant; their low index reflects high tolerance and stability against various pathogenic and entomological pressures. Conversely, cultivars C13 (2.95), C9 (2.97), and C8 (3.00) are highly susceptible; their high index reflects strong vulnerability to diseases, limiting their agronomic value under conditions of high pathogenic and entomological pressure.