Integrating botanicals in cowpea beetle management in Africa

Cowpea (Vigna unguiculata Walp.) is a major staple legume across several tropical developing countries in Africa, Asia, and South America. The largest production is in sub-Saharan Africa with Nigeria being the highest producer. The major loss of this produce is annually caused by the cowpea beetle (Callosobruchus maculatus Fab.). The management of this beetle on a large scale relies solely on synthetic pesticides. Due to environmental issues, there have been extensive researches on alternative eco-friendly means of combating the beetle’s menace. Africa has not been left behind in the search. The use of botanicals has been practiced extensively in Africa. In diverse studies, we integrated the use of botanicals with cowpea variety and locational (geographical) influence on the mortality or biology of cowpea beetle. We observe various interactive effects of these factors on the beetle’s response. We also discovered that plant essential oil (EO) optimized the susceptibility of C. maculatus while enhancing the nutritional qualities of cowpea simultaneously. Cowpea beetle susceptibility to EO treatments remained consistent across generations and correlated with the down-regulation of detoxifying enzymes (cytochrome P450 and GST) genes. Our research findings will aid the IPM of C. maculatus and form the basis for future research.