Industry Views of Monitoring and Mitigation of Herbicide Resistance

Abstract

Managing the risk of herbicide resistance (HR) is strategically important to leading herbicide technology providers and is the focus of the Global Herbicide Resistance Action Committee (HRAC), an organization with representation from 8 major companies, working as a part of CropLife International (Brussels, Belgium). Early detection of HR, understanding the extent of HR in a defined area, and mitigation of resistance through efforts to limit its spread are important aspects of managing HR. Monitoring for HR populations has been employed by weed scientists for both early detection and to define the extent of resistance (Baumgartner et al. 1999; Beckie et al. 2013; Davis et al. 2008; Falk et al. 2005; Owen et al. 2007). Methods used to monitor for resistance have included random or nonrandom seed sample collection from fields, followed by resistance bioassay (field surveys); market research surveys of farmers and weed management experts; and tracking farmer performance inquiries, followed by appropriate field evaluation and testing. Each method has advantages and disadvantages in costs, accuracy, and effectiveness to address HR management goals. Before embarking on a resistance-monitoring program, the objectives, probability of achieving those objectives, and the associated resource needs should be carefully considered. Based on a review of existing monitoring studies and company experiences, HRAC offers the following considerations for herbicide resistance monitoring: