Evaluation of XL370A-derived maize germplasm for resistance to leaf feeding by fall armyworm

Authors: Abel, Craig; Coates, Brad; Millard, Mark; Williams, William; Scott, Marvin

Submitted to: Southwestern Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/10/2019
Publication Date: 3/26/2020
Citation: Abel, C.A., Coates, B.S., Millard, M.J., Williams, W.P., Scott, M.P. 2020. Evaluation of XL370A-derived maize germplasm for resistance to leaf feeding by fall armyworm. Southwestern Entomologist. 45(1):69-74. https://doi.org/10.3958/059.045.0107.
DOI: https://doi.org/10.3958/059.045.0107

Interpretive Summary: The fall armyworm reduces maize yields, primarily by damaging developing leaves and ear tissue. Economic control of this pest is challenging and years of insecticide use has selected for resistance to several classes of insecticide and Bt-maize grown in Brazil, Puerto Rico and the southeastern U.S. The discovery of native sources of maize resistance to this pest is needed. For this study, maize lines derived from germplasm XL370 were tested for resistance to leaf feeding fall armyworm. The maize entries were grown in the field and plants infested with fall armyworm larvae. Damage to the maize leaves was recorded at 7 days and 14 days after infestation. Maize lines GEMN-0095, GEMN-0096, and GEMN-0133 were moderately resistant to fall armyworm across both years of testing. Another maize lines, GEMN-0048, was variable in its response to fall armyworm feeding. These lines are adapted for growth in temperate areas, e.g. the U.S. Corn Belt, and are ready for breeders to use to improve maize.

Technical Abstract: The fall armyworm, Spodoptera frugiperda (J.E. Smith) (Lepidoptera:Noctuidae), is an economically important insect with larvae damaging maize (Zea mays L.) leaves and ear tissue. The pest has become resistant to several classes of insecticide and Bt-maize grown in some geographic areas. Once discovered and characterized, native sources of maize resistance to this pest could be effectively integrated with existing control tactics. The objective for this study was to test experimental lines derived from maize germplasm, XL370A, for resistance to leaf feeding by fall armyworm. Plants were grown in the field in 2018 and 2019, artificially infested with fall armyworm, and leaf damage scores recorded. Experimental maize lines GEMN-0095, GEMN-0096, and GEMN-0133 were moderately resistant and not significantly different from one another across both years. Cuba 94 was not significantly different from these three entries with the exception of having higher 7-day damage scores in 2019. There was some variability in damage within experimental line, GEMN-0048. These experimental lines are adapted for growth in temperate regions and may provide maize breeding programs with useful levels of resistance to fall armyworm.