Spodoptera frugiperda in Togo 5 years on: early impact of the invasion and future developments

Abstract

The infestation of the fall armyworm (FAW), Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) in Africa since 2016 has been a major threat to maize production. Previous studies in Togo and Ghana from 2016 to 2018 did not correlate FAW infestation to yield losses. Thus, the aim of this study which assesses the impact of FAW infestation by inspecting 150 maize farms throughout the five Agro-Ecological Zones (AEZs) of Togo for FAW plant damage, and third instar larvae were used to infest 10-day-old maize plants in netted plots under controlled conditions at an experiment station (Station d'Expérimentations Agronomiques de Lomé) in 2019 and 2020. As control plots at the experiment station, plots were both netted and treated with emamectin benzoate, simply netted, or open to natural infestation. The number of larvae, egg masses, percent damaged plants, and damage proportions of leaves and ears were scored until harvest. Infestations and damages on maize plant throughout Togo were similar between the two years but were higher in the southern part of the county (AEZ5). At the experiment station, the yield losses were significantly considerable and increased from 25% infestation. The losses were 0.37 t ha−1 for 25% infestation, 0.34 t ha−1 for 30%, 0.59 t ha−1 for the open plots, 0.70 t ha−1 for simple netted and 50% infestation, 1.03 t ha−1 for 75%, and 1.27 t ha−1 for 100% infestation. This current study suggested thorough inspection on maize farms to set off management practices from 25% of infestation.

The natural control agents of the fall armyworm, Spodoptera frugiperda in Togo: moderating insecticide applications for natural control of the pest?

“…But due to the indiscriminate application of insecticides in the invaded areas, the population evolutions and potentiality of natural control of the indigenous agents are poorly known. However, in Togo, infestation of FAW was three times lower from 2018 to 2020 compared to the previous two years following the invasion (Ko et al 2020a(Ko et al , 2022. Thus, the aim of this study was to identify,evaluate the geospatial distributions, and the impacts of insecticides applications on indigenous entomopathogenic virus, bacteria, fungi and nematodes, parasitoids, and predators established with FAW populations during the seven years following the invasion of the pest in Togo.…”