Effectiveness of Two Entomopathogenic Nematodes (Nematoda: Rhabditida) Populations in Controlling Fall Armyworm (Spodoptera Frugiperda) Lepidoptera: Noctuidae on Maize

The fall armyworm, Spodoptera frugiperda (Lepidoptera: Noctuidae), is a recent invasive pest significantly impacting maize production and food security in sub-Saharan Africa. While chemical insecticides have offered the most effective control in Ghana, their detrimental effects on human health and the environment necessitate the urgent exploration of alternative, environmentally friendly options. This study compared two entomopathogenic nematodes populations, Heterorhabditis bacteriophora and Steinernema carpocapsae, against a control group (no application) for their efficacy in managing fall armyworm on maize. In the second experiment, S. carpocapsae significantly outperformed both H. bacteriophora and the control in terms of seed weight, achieving a 12.9% increase over the former and a remarkable ninefold improvement over the latter. The first experiment, however, showed no significant difference in seed yield (59 g, 32 g, 2 g) between the two nematode treatments, S. carpocapsae demonstrated the highest yield within this group. Notably, the control group exhibited the highest degree of foliage damage (4.7; 5.0) on a 1-5 scale throughout the study period. Overall, this study demonstrates the superior efficacy of S. carpocapsae compared to H. bacteriophora in controlling fall armyworm on maize. These findings provide valuable understandings for advancing the practical application of entomopathogenic nematodes as a sustainable and eco-friendly biocontrol measure against this devastating pest, contributing to enhanced food security in sub-Saharan Africa.