Simões Araujo, André Lucas, authorGaines, Todd, advisorDayan, Franck, committee memberFonte, Steven, committee member2024-01-012024-12-292023https://hdl.handle.net/10217/237337With the impending release of genetically engineered sugar beet varieties with resistance to glyphosate, dicamba, and glufosinate, significant changes are expected in weed management practices, particularly with regards to in-crop weed control. Glyphosate is used during fallow and in-crop periods, while dicamba is commonly employed in fallow applications, specifically targeting glyphosate-resistant weed species. This study provides insights into the resistance status and frequency of resistance in problematic weed species to the three active ingredients in sugar beet systems across Colorado, Nebraska, and Wyoming. While numerous studies have highlighted the widespread prevalence of glyphosate-resistant kochia and Palmer amaranth across the United States, there is limited research focusing on these species within the context of a sugar beet system. Additionally, our findings reveal the first occurrence of glyphosate-resistant and dicamba-resistant Palmer amaranth populations in Colorado, and dicamba-resistant kochia populations within a sugar beet system. Furthermore, we report that all dicamba-resistant kochia populations tested in Colorado lack a known target-site resistance mechanism, suggesting the involvement of a novel resistance mechanism. Surveys assessing glufosinate resistance in the sugar beet system have not been conducted until now, and we provide valuable baseline information on the resistance frequency for this herbicide prior to an anticipated increase in glufosinate use. To address the widespread issue of herbicide resistance in various crop systems, it is crucial to adopt alternative strategies that mitigate resistance evolution and maintain the long-term effectiveness of available herbicides. One promising approach is chaff lining, a harvest weed seed control method that has gained popularity in Australia due to its effectiveness in reducing populations of herbicide-resistant ryegrass, especially when combined with other weed control methods. However, the efficacy of chaff lining may be influenced by several factors, including crop and environmental factors, as reported in Australian literature. Scientific studies assessing the applicability and effectiveness of chaff lining in the United States are limited. Recognizing this research gap and aiming to explore the potential of chaff lining, our study investigated its applicability in field settings within the Central Great Plains region of the United States. Through our research, we provide insights into chaff lining efficacy of and highlight the potential inconsistencies that may arise in suppressing weed seeds using this method. Notably, we demonstrate that various factors, including location and environmental conditions, may be involved and impact the effectiveness of chaff lining as a weed management strategy. These findings underscore the importance of integrating chaff lining with other weed management methods to achieve effective and sustainable weed control. Chaff lining, like any other weed management strategy, should not be solely relied upon. Instead, it should be implemented as part of an integrated approach to ensure its long-term effectiveness.born digitalmasters thesesengCopyright and other restrictions may apply. User is responsible for compliance with all applicable laws. For information about copyright law, please see https://libguides.colostate.edu/copyright.TextEmbargo expires: 12/29/2024.