Performance of Bt maize Against Spodoptera frugiperda (lepidoptera: noctuidae) in a tropical ecotone

The fall armyworm, Spodoptera frugiperda J.E. Smith (Lepidoptera: Noctuidae), a major pest of maize, is responsible for significant agricultural productivity losses globally. One of the most effective control strategies relies on genetically modified (GM) maize cultivars expressing Bacillus thuringiensis (Bt) genes, which produce insecticidal proteins such as Cry and Vip3Aa. Although effective, the widespread and continuous use of Bt technology requires regular assessment due to the potential for resistance development, which may undermine long-term pest control. This study evaluated the susceptibility of S. frugiperda to Bt proteins under field conditions by comparing two Bt maize cultivars (NK 555 VIP3 and DKB 390PRO4) with two conventional cultivars (DKB 3800RR and P3889 R) in a randomized block design over two cropping seasons (2022 and 2023). Bt maize cultivars showed high efficacy, with negligible foliar damage, whereas conventional cultivars exhibited larval infestation from 29 days after sowing (DAS), resulting in moderate damage. These findings reaffirm the effectiveness of Bt maize in controlling S. frugiperda and highlight the global importance of ongoing resistance monitoring to preserve the sustainability of Bt-based pest management strategies.