Geographic Distribution of Bacillus thuringiensis Cry1F Toxin Resistance in Western Bean Cutworm (Lepidoptera: Noctuidae) Populations in the United States

Authors

Brad S. Coates, USDA-ARS, Corn Insects & Crop Genetics Research Unit, Ames, IAFollow
Craig A. Abel, USDA-ARS, Corn Insects & Crop Genetics Research Unit, Ames, IAFollow
Katharine A. Swoboda-Bhattarai, University of Nebraska - LincolnFollow
Debra E. Palmquist, USDA-ARSFollow
Débora Goulart Montezano, University of Nebraska-LincolnFollow
Sarah N. Zukoff, Kansas State UniversityFollow
Yangzhou Wang, Jilin Academy of Agricultural Sciences,
Jeffery D. Bradshaw, University of Nebraska-LincolnFollow
Christina D. DiFonzo, Michigan State UniversityFollow
Elson Shields, Cornell UniversityFollow
Kelley J. Tilmon, The Ohio State UniversityFollow
Thomas Hunt, University of Nebraska-LincolnFollow
Julie A. Peterson, University of Nebraska-LincolnFollow

ORCID IDs

http://orcid.org/0000-0001-5157-3536 Katharine A. Swoboda-Bhattarai

Date of this Version

2020

Comments

Journal of Economic Entomology, XX(XX), 2020, 1–8

doi: 10.1093/jee/toaa136

Abstract

The western bean cutworm (WBC), Striacosta albicosta (Lepidoptera: Noctuidae), can be a severe pest of transgenic corn in the western Plains and Great Lakes regions of North America, including on hybrids expressing the Bacillus thuringiensis (Bt) Cry1F toxin. The level and geographic distribution of Cry1F resistance are not completely known. Neonate S. albicosta from 10 locations between Nebraska and New York state were subjected to dose–response trypsin-activated native Cry1F toxin overlay bioassays. In 2017, the mean estimated lethal concentration causing 50% larval mortality (LC50) ranged from 15.1 to 18.4 μg Cry1F cm−2, and were not significantly different among locations. In 2018, LC50 estimates at Scottsbluff, NE (22.0 μg Cry1F cm−2) and Watertown, NY (21.7 μg Cry1F cm−2) were significantly higher when compared to locations in Michigan (15.8 μg Cry1F cm−2). Significantly lower 14-day larval weight among survivors was correlated with higher Cry1F dose. Results from this study indicate that S. albicosta survivorship on purified Bt Cry1F toxin shows a relatively even distribution across the native and range expansion areas where seasonal field infestations typically occur.