Molecular characterization of pests (Chrysomelidae: Bruchinae) of beans (Phaseolus vulgaris) in the Republic of Congo

Abstract

The bean Phaseolus vulgaris is widely consumed by the Congolese population, because it is rich in protein and has a good nutritional quality. Beetles of the subfamily Bruchinae are pests of bean seeds in the field and storage in the Republic of Congo (RC). Their attacks cause a reduction in seed weight, leading to a decrease in the nutritional and commercial value of the seeds. The purpose of our study was to identify the post-harvest diversity of bean bruchids in two bean producing regions in the Congo (Niari and Bouenza) using molecular taxonomy (12S rRNA marker). The bean weevil, Acanthoscelides obtectus (Say), and cowpea weevil, Callosobruchus maculatus (Fabricius), were identified. Acanthoscelides obtectus, recognised as the main pest of beans, was found in all ten localities sampled, whereas C. maculatus, recognised as the main pest of pigeon peas (Cajanus cajan) and chickpeas (Cicer arietinum), was found in two of the ten. Better knowledge of the diversity of bruchids present in the RC will make it possible to propose effective control methods with little impact on environmental and human health.

Keywords: Bruchids, common bean, barcoding, 12S rRNA marker