Assessment of impacts of fall armyworm, Spodoptera frugiperda (Lepidoptera: Noctuidae) on maize production in Ghana

Abstract

Spodoptera frugiperda was considered an insect pest only in the Americas until its first report in African countries in 2016. In this study, farmers and agricultural officials in Ghana were interviewed on their perceptions and knowledge of the pest, on infestation and maize yield variations across years, and on management practices. Farms were inspected to determine the infestation level of 100 plants per hectare. Interviews revealed that farmers were familiar with the larval stages of this pest and noticed that the pest occurred throughout the year, but populations of S. frugiperda increased only during cropping seasons. Infestation levels reported by farmers in surveys were much lower in 2018 (30.38%) than in 2017 (80.92%). Farm inspections confirmed that infestation levels were much lower in 2018 (20.90%) than 2017 (73.70%). The belt formed by Guinea Savannah, Transitional Zone, and Semi Deciduous Forest Agro-Ecological Zones (AEZs) recorded the highest infestations while the lowest were observed from the Sudan Savannah and Tropical Rain Forest AEZs. Insecticides were the most commonly used tactic to manage populations of this new pest. Maize yields increased across Ghana between 2013 and 2015 from 1.52 to 1.73 t/ha, decreased between 2015 and 2017 to 1.55 t/ha, and increased to 1.69 t/ha in 2018. The impact of fall armyworm injury to maize production is discussed.