This project builds on previous Illinois Soybean checkoff-funded research documenting reduced glufosinate sensitivity in four Illinois waterhemp populations. Researchers are investigating how temperature and herbicide rate influence herbicide performance and examining the biological mechanisms behind resistance to help sustain effective postemergence (POST) control options in soybean production.

• Glufosinate is one of the few remaining effective POST herbicides for waterhemp control in soybean.
• Four Illinois waterhemp populations have demonstrated decreased sensitivity to glufosinate.
• Early findings suggest resistance may be driven by enhanced metabolic detoxification.
• Resistant and sensitive populations respond differently to temperature, which may impact field performance.
• Understanding resistance mechanisms is critical to slowing resistance evolution and preserving herbicide efficacy.

• Refines recommendations to optimize glufosinate performance under varying temperature conditions.
• Reduces the likelihood that resistant individuals survive and contribute to future resistance issues.
• Improves long-term weed management strategies by clarifying how resistance develops.
• Supports the potential development of rapid diagnostic tools for resistance detection.
• Helps protect one of the few remaining effective herbicide tools for managing waterhemp.

• Dr. Patrick Tranel, Ainsworth Professor & Associate Head, University of Illinois Urbana-Champaign
• Dr. Aaron Hager, Professor & Extension Weed Science Specialist, University of Illinois Urbana-Champaign
• Dr. Amit Rai, Assistant Professor, University of Illinois Urbana-Champaign

• University of Illinois greenhouse and controlled-environment growth chambers

Dr. Patrick Tranel
Ainsworth Professor & Associate Head
University of Illinois Urbana-Champaign
217-333-1531
tranel@illinois.edu