Inventory of the entomofauna associated with the cultivation of sweet corn in Senegal: Report of the fall armyworm Spodoptera frugiperda

Abstract

Objective: The objective of this work was to draw up an inventory of the entomofauna associated with the cultivation of sweet corn (Zea mays L. ssp saccharata) in the Niayes in Senegal. Methodology and Results: A monitoring and sampling was carried out between June and August 2017 at the experimental station of the Senegalese Institute for Agricultural Research (ISRA) in Sangalkam (Dakar), the insects collected were identified by the laboratory of terrestrial invertebrates from IFAN/ Cheikh Anta Diop University of Dakar. It has been listed 75 species divided into 10 orders for 28 families mainly Coleoptera (41%), Orthoptera (12%), Diptera (12%), Hymenoptera (12%) and Lepidoptera (11%). The Shannon H index indicates a diversity value of 3.4, and the regularity index gives the value of 0.78, which reveals an average diversity with a minority of species dominating the environment. A higher abundance and diversity of entomofauna associated with maize has been noted during the flowering stage to ear maturation this exploration work was able to detect an invasive pest in Senegal: the fall armyworm, Spodoptera frugiperda. The study also revealed a significant imbalance between pests and auxiliaries of maize in the environment with more than 80% of the insects encountered being pests. In addition, this study has enabled the reporting and confirmation of the fall armyworm in Senegal, which without monitoring and intervention could be a real threat to food security in Africa and in Senegal in particular. Conclusion and Application of Findings: This study allowed the updating of the entomofauna of sweet corn in the Niayes area in Senegal. The results reveal in particular a significant imbalance of the maize entomofauna in favour of pests, but also the report of the polyphagous pest S. frugiperda. These results can constitute an important basis for the development of sweet corn crop protection strategies in Senegal