EVALUATION OF VEGETATIVE GROWTH STAGE SUSCEPTIBILITY OF QUALITY PROTEIN MAIZE TO FALL ARMYWORM (Spodoptera frugiperda SMITH) INFESTATION
NJE Vol. 42(1) : 212-220, 2026
DOI.10.36108/NJE/6202/24.0151
Musa, N., Usman, M. S., Adamu, R. S. and Utono, I. M
Department of Crop Protection, Faculty of Agriculture, Institute for Agricultural Research, Ahmadu Bello University, Zaria
Abstract
Screen-house experiments were conducted during the 2020 and 2021 wet seasons at the Department of Crop Protection, Ahmadu Bello University, Zaria, Nigeria, to determine the susceptibility of different vegetative growth stages of Quality Protein Maize (QPM) variety SAMMAZ 36 to damage by the fall armyworm (Spodoptera frugiperda). The experiments were laid out in a Completely Randomized Design (CRD) with three replications. Maize plants were grown in plastic pots placed inside wooden cages and artificially infested with six second-instar larvae at early-whorl (V4), mid-whorl (V8), and late-whorl (V12) growth stages corresponding to 2, 4, and 6 weeks after emergence, respectively. Leaf damage was assessed at one and two weeks after infestation using a 1–5 rating scale, while cob damage and grain yield were evaluated at maturity. Results from both seasons showed that plants infested at the early-whorl stage have significantly higher leaf damage ratings (3.25) compared to mid- and late-whorl stages. In contrast, the late-whorl stage had the highest cob damage rating (3.00) and the lowest grain yield. The findings indicate that the early-whorl stage is the most susceptible to foliar damage, while infestation at the late-whorl stage results in greater cob damage and yield reduction. The study concludes that effective fall armyworm management should commence at early vegetative stages and be sustained through later stages to minimize economic losses in QPM production.
Keywords: Fall Armyworm; Quality Protein Maize, Early, Mid, Late-whorl Vegetative Growth Stage