Critical Time for Weed Removal in Corn (\u3ci\u3eZea mays\u3c/i\u3e L.) as Influenced by Pre Herbicides

A weed control program that utilizes PRE herbicides and ensures a timely post-emergence weed removal could protect growth and yield of corn. The use of pre-emergence (PRE) herbicides for weed control could reduce the need for multiple POST applications of glyphosate in glyphosate-tolerant (GT) corn and provide an additional mode of action for combating glyphosate-resistant weeds. Thus, field studies were conducted in 2017 and 2018 at Concord, NE with the following objectives develop weed management recommendations that considers soil applied herbicides and determine proper timing of glyphosate based on the crop growth stage. Therefore the material in this thesis is presented in three chapters: Chapter 1 outlines the integrated weed management, critical period of weed control, and pre-emergence (PRE) or post-emergence (POST) herbicide use in corn. Chapter 2 determines the critical time for weed removal in glyphosate-tolerant corn without pre-emergence (PRE) herbicide and atrazine or Verdict-Zidua applied pre-emergence (PRE). Chapter 3 determines how the timing of weed removal and PRE herbicides application could influence growth and yield of glyphosate-tolerant corn. Advisor: Stevan Z. Knezevi