Multi-state assessment of electrocution for late-season weed control in soybean in the Central United States

Abstract The increasing prevalence of herbicide-resistant weeds underscores the need to integrate non- chemical weed management approaches in soybean. Weed electrocution may be a viable option; however, limited research exists on the subject. A multi-state study was conducted to evaluate electrocution as a late-season weed control method in soybean across six Midwestern states, including Illinois, Indiana, Iowa, Kansas, Missouri, and Nebraska. The Weed Zapper™ electrocution implement was assessed across thirteen site-years during 2021 and 2022. The objectives of this study were to (i) evaluate the efficacy of weed electrocution on various weed species at travel speeds of 4.8 and 8.1 km h⁻¹, and (ii) compare the efficacy with other commercially available weed control options. Other non-chemical weed control treatments, which varied by location and were evaluated at selected site-years, included an inter-row cultivator, a tine cultivator, a row shaver, and a weed wiper. Weed species differed in their responses to electrocution, with the greatest control observed for giant ragweed (85%) at 14 d after treatment (DAT). Waterhemp control ranged from 43% to 78% across seven site-years, with ≥70% control achieved at four site-years. Averaged across weed species, control did not differ between electrocution speeds at 7 DAT, 14 DAT, or at soybean harvest. Weed electrocution generally provided similar or lesser control than other non-chemical treatments. In Illinois, waterhemp control with electrocution (78%) was comparable to single (65%) and sequential pass (88%) inter-row cultivation at 14 DAT in 2022. In Kansas, electrocution provided similar Palmer amaranth control (40%) to the row shaver in 2022, but lesser control in 2021 (50% vs. 73%). The results from this study suggest that weed electrocution could be a component of integrated weed management for late-season weed escapes in soybean.