Field Evaluation of Bio-Pesticides and Selected Insecticides Against Spodoptera frugiperda (Lepidoptera: Noctuidae) in Maize with Receptor-Ligand Modelling of Spinetoram

The fall armyworm, Spodoptera frugiperda (J.E. Smith) is a destructive pest that causes negative impacts on maize production. The efficacy of bio-pesticides and selected insecticides were evaluated during 2024-2025 in field trials against the fall armyworm. It was determined that Spinetoram 11.70% SC was the most effective resulting in an 83.50% infestation reduction and the lowest larvae/plant population of 0.58. Emamectin benzoate 5% SG was also effective (0.71 larval/plant and reduction percentage 79.57%). Bio-pesticides such as Bacillus thuringiensis var. kurstaki, Metarhizium anisopliae and Beauveria bassiana were slightly less toxic compared to the chemical insecticides with reduction percentage of 62.25, 59.27 and 57.20 respectively. Spinetoram also produced the highest grain yield (44.00 q/ha), whereas the highest cost–benefit ratio was recorded in Emamectin benzoate (1:7.08). Further, we investigated molecular docking of spinetoram using PyRx and determined that strong binding affinity of Spinetoram with target proteins of fall armyworm. The most favourable interaction was observed with the GABA receptor display a binding energy of –10.7 kcal/mol, while interaction with nicotinic acetylcholine receptor (nAChR) showed a binding energy of –6.9 kcal/mol. The ligand-protein complexes were stabilized mainly by hydrogen bonding and hydrophobic interactions.