Zhang, Ti , Johnson, Eric N., Mueller, Thomas C., & Willenborg, Christian J.; “Early Application of Harvest Aid Herbicides Adversely Impacts Lentil;” Agronomy Journal, 2017, 109(1), 239-248; DOI: 10.2134/agronj2016.07.0419.
Applying harvest aid herbicides can dry down lentil (Lens culinaris Medik.) crops evenly and quickly, and can help control late-emerging weeds. However, improper application timing may reduce yield and quality, and leave unacceptable herbicide residues in seed, which can cause commercial issues when marketing lentil. The objective of this research was to determine the response of lentil to various application timings of glyphosate, saflufenacil, and the combination of these two herbicides. A field experiment consisting of a randomized complete block design was run at Saskatoon and Scott, SK, Canada in 2012, 2013, and 2014 to address the objective. Application of harvest aid herbicides before 30% seed moisture content reduced seed yield and thousand seed weight up to 25 and 8%, respectively. Moreover, application timings before 30% seed moisture resulted in lentil seed samples exceeding residue levels of 2.0 and 0.03 mg kg–1 for glyphosate and saflufenacil, respectively. Adding saflufenacil to glyphosate did not reduce glyphosate residue in lentil seed compared to glyphosate applied alone. However, this tank mixture significantly reduced seed residues of saflufenacil and improved crop desiccation compared with either glyphosate or saflufenacil applied alone. Our data lead us to conclude that a tank mix of saflufenacil+glyphosate should be recommended for crop desiccation and pre-harvest weed control in lentil over using either product alone. In addition, it is critical to ensure applications of glyphosate or saflufenacil are not made prior to 30% seed moisture in lentil crops. FULL TEXT