Evaluation of 21 Thailand Maize Germplasms for Resistance to Leaf Feeding Spodoptera frugiperda (Lepidoptera: Noctuidae)

Abstract: Native to the Americas, the fall armyworm, Spodoptera frugiperda (J.E. Smith) (Lepidoptera:Noctuidae), is a recent invasive pest of Africa and Asia. This insect causes economic damage to maize (Zea mays L.) primarily through leaf and ear tissue feeding. The pest is resistant to several classes of insecticide and several Bt-maize toxins. Native resistance in maize to fall armyworm could be used with existing control tactics to enhance control of this insect. The objective for this study was to evaluate maize germplasm, developed from Thailand and maintained by the U.S. National Plant Germplasm System, for resistance to leaf feeding fall armyworm. Plants were grown in the field and artificially infested at the seven-leaf stage with fall armyworms. Visual rating scores for leaf feeding damage were recorded at 7 and 14 days post infestation. Scores for maize germplasm Ames 26254 were not different than the resistant check, GT-FAWCC(C5), and germplasm PI 506347 and PI 690324 were not significantly different from Ames 26254. In total, five Thailand maize germplasms received 14-day damage scores of ≤ 6.0 across both years of testing and were considered moderately resistant to fall armyworm leaf feeding. These maize germplasms are tropical and require breeding to adapt progeny for research in temperate areas.