Issue No. 3, Article 3/April 10, 2009
Wheat Growth Stage and Herbicide Applications
Recent crop condition reports indicate that approximately 75% of the Illinois winter wheat crop is rated as good or excellent. Herbicide applications to control certain winter annual and perennial weeds must be properly timed to provide good weed control and minimize the potential for crop injury. Applications made to actively growing weeds and during periods of warm air temperatures generally provide more effective and complete weed control as compared with applications made during cold, cloudy conditions.
The labels of all herbicides commonly used for weed control in Illinois wheat have application restrictions based on wheat developmental stage. Most products commonly used in Illinois indicate that applications must be made before the wheat jointing stage. Table 1 presents information derived from the herbicides labeled for use in small grains. Before making any herbicide application, consult the respective herbicide label for additional information.
If you are considering applying a herbicide with liquid nitrogen as the carrier, be sure to consult the label beforehand. Not all herbicides allow applications with liquid nitrogen as the carrier, and those that do might have specific recommendations with respect to including or excluding other spray additives or their application rates.--Aaron Hager