Stakeholder Assessment of Corn-Soybean Weed Management Practices and Targeted Spraying Technologies Perceptions

Zaim Ugljic¹Ahmadreza Mobli¹Maxwel Coura Oliveira²Christopher A Proctor³J Anita Dille⁴Rodrigo Werle^1*

• ¹University of Wisconsin-Madison, Madison, United States
• ²BASF Digital Farming GmbH, Cologne, Germany
• ³Department of Agronomy and Horticulture, College of Agricultural Sciences and Natural Resources, University of Nebraska-Lincoln, Lincoln, Nebraska, United States
• ⁴Department of Agronomy, College of Agriculture, Kansas State University, Manhattan, Kansas, United States

A survey was conducted from fall 2021 to spring 2022 to investigate currently adopted chemical weed control strategies and the primary end-of-season weed escapes (left uncontrolled due to herbicide-resistance or late emergence) in corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] cropping systems across the Western U.S. Midwest Region (WUMR: Kansas and Nebraska) compared to the Eastern U.S. Midwest Region (EUMR: Illinois, Minnesota, and Wisconsin).Additionally, the survey assessed stakeholder awareness and perceptions regarding novel targeted spraying technologies, offering valuable insights into their potential role in future weed management.Survey responses (128 participants) indicated that over 50% of growers used a two-pass herbicide application program [preemergence (PRE) followed by postemergence (POST) with layered residual] in soybean and corn across both regions in 2021. The top weed escapes in WUMR corn fields were Palmer amaranth (Amaranthus palmeri S.Wats.), waterhemp [Amaranthus tuberculatus (Moq.) J.D.Sauer], and foxtail species (Setaria spp.), while for soybean fields, Palmer amaranth, waterhemp, and volunteer corn were most common. Conversely, EUMR respondents primarily reported foxtail spp., waterhemp, and giant ragweed (Ambrosia trifida L.) escapes in corn and waterhemp, giant ragweed, and volunteer corn in soybean fields. Over 49% of respondents believe that novel targeted spraying technologies could help control late season weed escapes. However, more than 75% are unsure whether these technologies will be adopted in the operations they manage in the future, with 48% indicating the need of more information to support their decision. The survey results showed a greater reliance on commercial applicator services in the EUMR than WUMR, highlighting the potential role of commercial applicators in advancing effective herbicide strategies and targeted spraying technologies adoption while reducing the need for farmers to invest in new equipment within the EUMR region. This survey highlights substantial opportunities for targeted herbicide application technologies research and outreach education involving regulatory agencies, spray manufacturers, chemical companies, decision influencers, University Extension and other parties.