Evaluating Founding Landraces of Maize Population PI 674097 for Resistance to Leaf-Feeding Spodoptera frugiperda

Abstract. Fall armyworm, Spodopera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), a maize (Zea mays L.) pest native to the Americas, is a recent invasive insect of Africa, Asia, and Oceania. Resistant to several insecticide classes and toxins of Bt-maize, the insect damages maize by feeding on leaf, tassel, and ear tissues. Using native resistance in maize with existing tactics could improve control. The objective of the study was to evaluate resistance to leaf-feeding fall armyworm in maize population PI 674097 and founding landraces used to develop the germplasm. Plants grown in the field and artificially infested at the seven- or eight-leaf stage were visually scored for leaf-feeding damage at 7- and 14-days post infestation. All scores for NSL 283507, PI 498583, PI 583912, and PI 674097 were less (i.e., more resistant) than those of susceptible check GEMN-0131. In 2022, 14-day scores for PI 674097 were not different from those of resistant check Mp708 (3.6 ± 0.5 and 2.7 ± 0.5, respectively). PI 674097 was variable in response to lead feeding by fall armyworm, with individual plants having a range of 14-day scores from 2 (resistant) to 7 (susceptible) across both years of testing. The variability might be useful when selecting greater resistance to the pest.