Endemicity of Fall Armyworm, Spodoptera frugiperda (Lepidoptera : Noctuidae), and it’s damages to maize in South Benin (West Africa)

Abstract

The present work is aimed at determining the presence of S. frugiperda and its damages to maize leaves and ears throughout the seasons in South Benin (West Africa). Five trials were carried out on different plots and dates throughout 2021 year, beginning from April. For data collection, maize plants were frequently observed immediately after emergence to identify symptoms showing the presence of armyworms in the field, and the percentage of injured plants was determined. Also, harvested ears were peeled and the percentage of ears injured by S. frugiperda was determined. Globally, results indicated that S. frugiperda is endemic to the district of Abomey-Calavi, in South Benin, West Africa. Nevertheless, damages caused to the plants and ears varied according to the planting dates. When sown in April, the plants and ears were slightly damaged. When sown on May 1, damages caused to the plants and ears slightly increased compared to plants sown about 2 weeks before. In contrast, plants sown on May 15 as well as those sown on July 4, were severely injured. Finally, when the seeds were sown on October 11, damages to the ears were not severe. In view of these results, it is obvious that the armyworms were highly harmful to maize plants when they are sown in the time period from mid-May to July. This time corresponds to late- season plantings in South Benin. Research efforts should be directed on the Integrated Management of S. frugiperda that includes non-chemical solutions such as planting date.