This project will address farmer/applicator questions regarding best practices to manage large pigweeds (Palmer amaranth and waterhemp) in Enlist soybeans. Specifically, we will 1) compare sequential applications of Liberty and Enlist One in small plots, 2) evaluate Liberty efficacy in a range of temperature and humidity conditions in the field, 3) compare herbicide treatments in on-farm field trial, and 4) collect weed seed samples to screen for herbicide resistance.

1. Identify the herbicide combinations and sequences that provide the best control of large Palmer amaranth and waterhemp
2. Develop a greater understanding of the influence of humidity and temperature on the effectiveness of Liberty (glufosinate)
3. Develop an understanding of glufosinate sensitivity/tolerance in Palmer amaranth and waterhemp across Kansas
4. Identify the herbicide treatments and environmental conditions that have the greatest economic benefit.

The information generated in this project will help prolong the usefulness of an important herbicide (Liberty) by using it in the most effective way possible. Even when a research project directly addresses farmer questions and concerns, the acceptance of results increases when research is done locally at commercial scale. This project will also help slow the development of glufosinate-resistant Palmer amaranth and waterhemp populations by detecting them as soon as possible. We will communicate the results via KSRE field days, newsletters and other electronic communications, Extension fact sheets, and a peer-reviewed publication.

This project directly answers questions posed by farmers and agronomist regarding best practices for managing large pigweeds in Enlist systems. The data generated will inform recommendations for the best interval for a re-spray, and more field-based data to determine the environmental conditions in which Liberty will be effective.