Assessing varied maize germplasm lines for resistance to fall armyworm and corn earworm with agronomic quality consideration

Authors: Woolfolk, Sandra; Jeffers, Daniel; Read, Quentin; Hawkins, Leigh; Babiker, Ebrahiem

Submitted to: Florida Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/12/2026
Publication Date: N/A
Citation: N/A

Interpretive Summary: Fall armyworm (FAW) and corn earworm (CEW) are two important pests of maize. As a global pest, FAW caterpillars can cause damage from seedling to mature maize plants. On the other hand, CEW caterpillars mainly feed on ear tips, silk, and kernels of maize. The presence of these two insects in high numbers can have a devastating effect on the economic yield of maize. Because of this, an all-inclusive approach was taken in this study to evaluate various maize lines for FAW leaf feeding and CEW ear feeding resistance along with their agronomic performance. We found that CML122, CML139, and Mp97:160 maize lines were the most resistant to FAW, while FBLL and LH199 offered strong resistance to CEW with good agronomic qualities. Moving forward, we plan to cross these insect resistant maize lines with other high-performing lines and may use modern breeding techniques to speed up the process of creating better maize lines that are resistant to both insects and possess good agronomic traits.

Technical Abstract: The fall armyworm (FAW), Spodoptera frugiperda (J.E. Smith), is a major global pest of maize where the larvae can cause damage from vegetative to reproductive stages. The corn earworm (CEW), Helicoverpa zea (Boddie) 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 major effect in maize economic yield losses. A holistic approach in assessing potential maize germplasm lines is important since 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 FAW neonates and scored for leaf damage 14 days after infestation. Plants were evaluated for ear damage based on CEW 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 FAW were CML122, CML139, and Mp97:160. FBLL and LH199 were among the most resistant lines to CEW with good agronomic traits. Our next steps were 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.