Evaluations of the Enlist E3 & RR2XtendFlex

The Roundup Ready 2 XtendFlex (dicamba, glyphosate, and glufosinate- resistant) and Enlist E3 (2,4-D, glyphosate, and glufosinate- resistant) soybean systems have become the dominate herbicide resistant soybean platforms in Kentucky. Both platforms have provided benefits to Kentucky soybean farmers with the recent increase in glyphosate and PPO-resistant broadleaves, especially the Amaranthus species. The heavy use of the systems and heavy reliance on the growth regulators (dicamba and 2,4-D) has created scenarios of potential resistance selection. In 2022 numerous complaints of reduced dicamba and 2,4-D efficacy were reported, although no resistance events have yet to be confirmed. Additionally the recent implementation of forward moving reviews of all pesticides for ESA (Endangered Species Act) mitigations threatens the full utilization of all herbicides. In the face of both potential resistance and increased regulatory restrictions the evaluation of combinations of herbicides related to the soybean resistance traits (dicamba, 2,4-D, glyphosate, and glufosinate) and combinations of older chemistries such as group 1 (clethodim, quizalofop, etc) group 14 (fomesafen, lactofen, etc) and group 2 (cloransulam, imazethapyr, etc) is needed in both herbicide-resistant soybean platforms. Project Objective(s): • Evaluate the XtendFlex and Enlist E3 soybean systems utilizing herbicides in which the soybean platform has resistance to (dicamba or 2,4-D, glyphosate, and glufosinate). • Evaluate the Xtendflex and Enlist E3 soybean systems utilizing traditional or older soybean herbicides.