Experiences with Sharpen In Oklahoma

Due to the rapid adoption of no-till and/or limited tillage production practices many Oklahoma producers continue to struggle with their control of horseweed on their cotton acreage. Traditional glyphosate based herbicide programs have been extremely ineffective, even when attempting to control non-glyphosate resistant horseweed. In addition, the recent confirmation of glyphosate resistant horseweed within the state forces growers to consider alternative chemistries for the control of this problem weed. Although most of our horseweed germinates between December and March, reports of later germinating (closer to planting) horseweed continue to increase. Although hormone based herbicide programs (2,4-D or Dicamba) have been very effective the need for enhanced and extended control still exists. The recent availability of Sharpen herbicide provides growers with an effective option for preplant horseweed control in cotton. Studies were conducted in both 2009 and 2010 in order to evaluate the effectiveness of Sharpen for the control of horseweed in Oklahoma. Sharpen is also being considered as a desiccant and/or defoliant. This product was also evaluated in 2009 and 2010 in comparison to other currently labeled defoliation products.