Yield impact of larval infestations of the fall armyworm (Lepidoptera:Noctuidae) to midwhorl growth stage of corn [Spodoptera frugiperda]

Egg masses of fall armyworm, Spodoptera frugiperda (J. E. Smith), were artificially placed on corn at the midwhorl growth stage. Levels of infestation tested included egg masses on 5, 10, 15, 20, and 100% of the plants. Populations were assessed by leaf damage ratings. Yield parameters of grain weight, ear length, kernel number, ear damage, number of damaged kernels, and weight of 100 kernels were measured. Significant yield losses of 17% were sustained when 20 or 100% of the plants received egg masses. The relationship of leaf damage ratings and yield was linear and inverse. Yield losses were directly related to reduction in kernel numbers on ears from infested plants.