Assessing varied maize germplasm lines for resistance to fall armyworm and corn earworm (Lepidoptera: Noctuidae) with agronomic quality consideration

Abstract

The fall armyworm, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), is a major global pest of maize where the larvae can cause damage from vegetative to reproductive stages. The corn earworm, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae) is another major pest of maize where the larvae mainly feed on ear tips, silk, and kernels. Severe infestations by these two insect pests can have a major effect on maize economic yield. A holistic approach in assessing potential maize germplasm lines is important as agronomic qualities are considered to offer stakeholders insect-resistant lines with suitable agronomic performance. Varied germplasm maize lines were evaluated for resistance to fall armyworm and corn earworm along with their agronomic traits. The maize lines were infested at V-7 stage with fall armyworm neonates and scored for leaf damage 14 days after infestation. Plants were evaluated for ear damage based on corn earworm natural infestation by measuring feeding penetration depth along the ear. There was no significant difference in the leaf damage scores between 2022 and 2023 for all maize lines. However, some maize lines showed evidence of an increase or decrease in ear damage in 2022 compared to 2023. The most resistant lines to fall armyworm were CML122, CML139, and Mp97:160. FBLL and LH199 were among the most resistant lines to corn earworm with good agronomic traits. Our next steps are to make test crosses of these potential insect resistant lines with other lines that possess good agronomic traits and possibly utilize maize breeding technologies to accelerate the process in producing superior maize lines.