Assessment of potential biopesticide options for managing fall armyworm (Spodoptera frugiperda) in Africa

Abstract

The fall armyworm (FAW, Spodoptera frugiperda) originates from the tropical and sub‐tropical regions of the Americas. Recently it was reported for the first time in Africa and has since spread rapidly across more than 30 countries in the continent. Chemical pesticides are being promoted and used for FAW management, but where application practices and/or the active ingredients are unsafe there is a need to make effective, low‐risk products available. Given that biopesticides such as microbials and microbial extracts, macrobials and semiochemicals are generally considered to be lower risk options for pest management, they are a promising avenue for exploration. When used in conjunction with good crop management, they can help to keep pest levels under control, reducing the need to apply other pesticides. This study provides a basis for designing interventions to make biopesticides more widely available for FAW control in Africa. It summarizes assessments of the registered pesticides and biopesticides for 30 countries, 11 in FAW's native range and 19 in Africa. The report identifies biopesticide active ingredients (AI) which are registered for use against FAW and provides an assessment of how appropriate these will be for use by smallholder farmers in Africa. For each biopesticide AI identified, detailed profiles were developed which covered the efficacy of the AI against FAW; the human health and environmental hazards associated with the AI; the agronomic sustainability of the AI; and whether or not the AI is practical for smallholder farmers to use. Using these data, a list of priority biopesticides for which follow‐up action is recommended was compiled. Fifty biopesticide AI were identified, which have been registered in one or more of the 30 countries for FAW management. Twenty‐three of these are recommended for follow‐up, for example field trials or bioassays.

Parasitoid Complex of Fall Armyworm, Spodoptera frugiperda, in Ghana and Benin

“…In Kenya and Tanzania, authors [19] mention egg parasitism rates by T. remus above 50%. However, it must be noted that eggs parasitized by T. remus remain at least four times longer in the field than unparasitized eggs because the duration of the egg stage is only two to three days during the warm summer months [16] whereas the development of T. remus at 25 • C lasts 12 to 13 days [52]. Furthermore, parasitized eggs are dark, and thus more visible than unparasitized ones.…”

“…Some authors [22] discussed the potential of using C. luteum in augmentative biological control. The challenge of using a larval parasitoid of S. frugiperda in augmentative biological control will be to find alternate rearing hosts for mass production, since S. frugiperda is not suitable for the mass production of larval parasitoids due to the cannibalistic behaviour of the larvae [16].…”

“…The sustainable management of this invasive pest, therefore, requires the development and dissemination of ecologically friendly crop protection methods. Biopesticides could be an option, but a recent analysis of the availability of biopesticides in Africa revealed that in many countries few active ingredients are registered and most of them are not yet registered against S. frugiperda [16]. Methods such as the use of botanicals have recently been suggested as another suitable option [10,16,17], but their wider use is constrained by availability and cost.…”

“…Biopesticides could be an option, but a recent analysis of the availability of biopesticides in Africa revealed that in many countries few active ingredients are registered and most of them are not yet registered against S. frugiperda [16]. Methods such as the use of botanicals have recently been suggested as another suitable option [10,16,17], but their wider use is constrained by availability and cost. Therefore, biological control approaches that exploit the use of parasitoids and predators become viable alternatives for the management of this pest, particularly among resource-constrained smallholder farmers.…”

The Efficacy of Alternative, Environmentally Friendly Plant Protection Measures for Control of Fall Armyworm, Spodoptera Frugiperda, in Maize

“…Altogether, a strong need exists to identify alternative solutions for farmers that would be effective, affordable, in line with Integrated Pest Management (IPM), and tailored to suite the local conditions and farming practices in Africa [12][13][14]. It is obvious to consider the actions smallholder farmers in Central America and Mexico are taking, as they have been managing fall armyworm (FAW) successfully for hundreds of years, even though the differences in agricultural systems should be accounted for.…”