Received: 17 February 2019 Accepted: 17 September 2019 Published online: 10 January 2020 DOI: 10.1002/agj2.20029 ARTICLE Pest Interaction in Agronomic Systems Weed control and response of yellow and white popcorn hybrids to herbicides Ethann R. Barnes 1 Nevin C. Lawrence 2 Stevan Z. Knezevic 3 Oscar Rodriguez 1 Suat Irmak 4 Amit J. Jhala 1 1 Dep. of Agronomy and Horticulture, Univ. of Nebraska-Lincoln, Lincoln, NE 68583 2 Panhandle Research and Extension Center, University of Nebraska-Lincoln, Scottsbluff, NE 69361 3 Northeast Research and Extension Center, Haskell Agricultural Lab., Univ. of Nebraska-Lincoln, Concord, NE 68728 4 Dep. of Biological Systems Engineering, Univ. of Nebraska-Lincoln, Lincoln, NE 68583 Correspondence Amit J. Jhala, Dep. of Agronomy and Horticul- ture, Univ. of Nebraska-Lincoln, Lincoln, NE 68583. Email: Amit.Jhala@unl.edu Current address Oscar Rodriguez, Conagra Brands, Inc Brook- ston, IN 47923. Abstract Popcorn (Zea mays L. var. everta) is an important crop to Midwestern US produc- ers. While there is considerable research on field corn and sweet corn sensitivity to herbicides, there is a lack of information on popcorn sensitivity to herbicides. Field experiments were conducted in 2017 and 2018 to evaluate herbicides labeled for yel- low popcorn in commercially available popcorn hybrids for weed control and crop response in Nebraska. The experiments were arranged in a split-plot design. The main plot treatments consisted of two white and six yellow popcorn hybrids. Ten sub-plot treatments consisted of nontreated control, weed-free control, and four pre-emergence (PRE) followed by postemergence herbicide treatments applied at labeled rates (1X) and double the labeled rates (2X). Across hybrids, PRE herbicide treatments resulted in 4–8% injury. Across all PRE herbicide treatments, a yellow hybrid, R265, displayed the greatest average plant injury (11%). At labeled rates, broadleaf weed control in both years, and foxtail control in 2017, ranged from 95–99% with all treatments; how- ever, foxtail control was limited (72–86%) for most treatments in 2018. Weed biomass reduction in all herbicide treatments ranged from 90–98% and 68–97% control in 2017 and 2018, respectively. Yield losses ranged from 0–7% in herbicide treatments, with a 42% yield loss in the untreated control. Although slight hybrid differences in her- bicide sensitivity were detected, the differences were not linked to popcorn color. Information reported in this research are the first that determined popcorn sensitivity to herbicides. 1 INTRODUCTION Popcorn (Zea mays L. var. everta) is an important field crop for many producers in the US Midwest. Popcorn is grown on nearly 90,000 ha of land annually in the United States (USDA NASS, 2018). Illinois, Indiana, Iowa, Kansas, Ken- tucky, Michigan, Nebraska, and Ohio are eight major con- tributing states for popcorn production in the United States Abbreviations: DA POST, days after postemergence application; DA PRE, days after pre-emergence application; DAT, days after treatment; fb, followed by; PRE, PRE, pre-emergence; POST, postemergence. © 2020 The Authors. Agronomy Journal © 2020 American Society of Agronomy (USDA NASS, 2018). Nebraska is the leading producer of popcorn in the United States, producing 160 million kg of the total 356 million kg popcorn produced overall (45% of the national production) on over 28,000 ha in 2012 (USDA NASS, 2018). The next three top popcorn producing states combined (Indiana, Illinois, and Ohio) produced 42% of the nation’s harvest in 2012 (USDA NASS, 2018). Popcorn is usually produced under contracts, which specify the hybrids and area to be planted (D’Croz-Mason & Waldren, 1978; Ziegler, 2001). The majority of popcorn is produced under conservation tillage systems (Pike et al., 2002). Popcorn emerges slower, produces narrower and more upright leaves, 458 wileyonlinelibrary.com/journal/agj2 Agronomy Journal. 2020;112:458–469.