Evaluation of twenty maize germplasms from Belize, French Guiana, Guyana, and Suriname for resistance to leaf-feeding Spodoptera frugiperda

Authors: Abel, Craig; Williams, William

Submitted to: Southwestern Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/29/2022
Publication Date: 9/16/2022
Citation: Abel, C.A., Williams, W.P. 2022. Evaluation of twenty maize germplasms from Belize, French Guiana, Guyana, and Suriname for resistance to leaf-feeding Spodoptera frugiperda. Southwestern Entomologist. 47(3):559-564. https://doi.org/10.3958/059.047.0303.
DOI: https://doi.org/10.3958/059.047.0303

Interpretive Summary: The fall armyworm was accidentally introduced into west Africa in 2016 and has since spread to over 70 countries in Africa, Asia, and Oceania. Estimated losses to agriculture in Africa alone are 9.4 billion U.S. dollars/year. A preferred host, maize yield losses are significant from fall armyworm feeding to the leaf, tassel, and ear. Because larvae often feed in areas of the plant protected from the outside environment, chemical control is difficult and the pest is also resistant to several classes of insecticide and maize that has been genetically modified to produce toxins to protect itself. Maize plants with natural defenses against fall armyworm feeding could help overcome these control issues. The objective for this study was to evaluate maize germplasm from four countries within the pest’s historic range, for resistance to leaf feeding fall armyworm. Field-grown plants were infested with fall armyworm larvae and leaf damage assessed 7 and 14 days later. Using this approach, we identified several new germplasm sources that are moderately resistant to fall armyworm leaf feeding and may be useful to breeding programs developing resistant maize.

Technical Abstract: The fall armyworm, Spodoptera frugiperda (J.E. Smith) (Lepidoptera:Noctuidae), is native to the Americas and a recent invasive pest of Africa, Asia, and Oceania. This insect causes economic damage to maize (Zea mays L.) through leaf, tassel, and ear tissue feeding. The pest is resistant to several classes of insecticide and Bt-maize grown in certain geographic areas. Native resistance in maize combined with existing control tactics could help overcome these control issues. The objective for this study was to evaluate maize germplasm from four countries within the pest’s historic range, for resistance to leaf feeding fall armyworm. Plants grown in the field and artificially infested at the seven-leaf stage, received visual rating scores for leaf feeding damage at 7 and 14 days post infestation. All scores for maize germplasm Ames 28786 (‘GIN II’) were not different than the resistant check, GT-FAWCC(C5). In 2020 and 2021, 14 day scores for NSL 283834 (‘Guyana 807’) (5.8 ± 0.3 and 4.9 ± 0.3, respectively) were not different than GT-FAWCC(C5) (5.3 ± 0.2 and 4.8 ± 0.3, respectively). These germplasm sources are moderately resistant to fall armyworm leaf feeding and may be useful to breeding programs developing resistant maize. In one of the two years of testing, three other germplasms, NSL 283833, NSL 283890, and PI 553088, received 14 day rating scores < 6.0 and further testing is required to determine their ability to resist leaf feeding fall armyworm. All of the maize germplasms tested are tropical populations and require breeding to adapt progeny for additional research in temperate areas.