The fall armyworm Spodoptera frugiperda (J.E. Smith), a new pest of maize in Africa: monitoring, damage evaluation and identification of natural enemies on production areas of Senegal

Abstract

The fall armyworm (FAW) Spodoptera frugiperda (J.E. Smith), an invasive pest of cereal crops in Africa, poses a real threat to food security in sub-Saharan African countries where cereals are the staple food. Since its appearance in Africa in 2016, the FAW has invaded almost all African countries due to its great dispersal capacity. Because of its resistance to a number of chemical pesticides but also the risks associated with the use of these, the search for an alternative method becomes essential. In order to report on the incidence of this pest and explore its associations with native natural enemies, a monitoring study of S. frugiperda populations, its damage as well as its natural enemies was carried out during the period of August to September 2020 in corn fields of two agro-ecological zones of Senegal and in the laboratory. Monitoring results show a heavy infestation with rates of up to nearly 75% of defoliated plants and more than 60% of attacked ears. The damage recorded remains low overall (score below 3/9). A wide range of auxiliary insects (17 families) made up of parasitoids and predators were identified in the field and in the laboratory as well as an endoparasitic nematode with a parasitism rate of 38.46% and a fungus in one of the sites. These results pave the way for the development of an approach to control CLA with these biological agents.