Evaluation of WideStrike (R) Cotton (Gossypium hirsutum L.) Injury from Early Season Herbicide and Insecticide Tank Mixes

A study was conducted in 2010 and 2011 at the West Tennessee Research and Education Center in Jackson, TN to evaluate the tolerance of Phytogen((R)) 375 WRF (WideStrike r) cotton to glufosinate or a premix of glyphosate and s-metolachlor alone or when tank mixed with selected insecticides used for the control of thrips. Significant differences in visual injury were caused by the herbicides and the insecticides in 2010, but not in 2011. Glufosinate delayed crop maturity in 2010, but did not delay maturity in 2011. Total yield was reduced by glufosinate application but not by insecticide treatment in 2010. Herbicide treatment did not affect yield in 2011 (P = 0.3496) but insecticide application increased yield. There was no interaction between herbicide and insecticide on total yield in 2010 or 2011. These data show that maturity might be delayed and yield decreased by an early-season glufosinate or glufosinate + insecticide application to WideStrike cotton. This measurable level of yield loss from glufosinate on WideStrike cotton differs from most previous research. The measurable level of yield loss in WideStrike cotton in this case might be due to early-season stress injury just prior to the glufosinate application.