Occurrence and Evaluation of Larval Developmental Stages of Fall Armyworm on Annual Crops in Southwestern Nigeria
Rosulu, H. O.
Department of Crop Production Technology, Yaba College of Technology, School of Agricultural Technology, Lagos, Nigeria.
Adanlawo, A. O.
*
Department of Crop Production Technology, Yaba College of Technology, School of Agricultural Technology, Lagos, Nigeria.
Quadri, S. A.
Department of Crop Production Technology, Yaba College of Technology, School of Agricultural Technology, Lagos, Nigeria.
Apari, O. O.
Department of Crop Production Technology, Yaba College of Technology, School of Agricultural Technology, Lagos, Nigeria.
Oyaniyi, O. M.
Department of Crop Production Technology, Yaba College of Technology, School of Agricultural Technology, Lagos, Nigeria.
*Author to whom correspondence should be addressed.
Abstract
Aims: This study aimed to evaluate the occurrence, larval development, host suitability, and yield effects of Fall Armyworm (Spodoptera frugiperda) on maize and selected alternative host plants to support informed pest management decisions.
Study Design: Laboratory and pot experiments arranged in a Completely Randomized Design.
Place and Duration of Study: School of Agricultural Technology Laboratory, YABATECH, during both rainy and dry seasons of 2022 - 2023.
Methodology: Larval development of Spodoptera frugiperda was assessed on maize, amaranthus, sweet potato, and cowpea. Head capsule width, body morphology, number of larval instars, and duration of larval and pupal stages were measured. Growth parameters and yield components of host plants were evaluated and compared with uninfested control treatments.
Results: Six larval instars were confirmed on all hosts. Mean growth ratios of head capsule width conformed to Dyar’s rule: 1.52 (amaranthus), 1.48 (maize), 1.50 (cowpea), and 1.54 (sweet potato). The total larval-pupal period was shortest on maize and amaranthus (14 days) and longest on cowpea and sweet potato (15 days). Strong linear relationships (R² ≥ 0.98) were found between instar progression and head capsule width. Infested plants showed significant reductions in leaf area, plant height, and leaf number compared to controls.
Conclusion: Maize and amaranthus are highly suitable host plants for Spodoptera frugiperda, supporting rapid larval development and causing significant growth and yield losses. These findings highlight the need for prioritized monitoring and integrated management strategies on both primary and alternative host crops.
Keywords: Fall Armyworm, maize, Amaranthus, sweet potato, cowpea, larval