Session B: Implications for waterhemp based on lessons learned from Palmer amaranth: The need for proactive herbicide resistance management


Presentations

Implications for Waterhemp Based on Lessons Learned from Palmer Amaranth: The Need for Proactive Herbicide Resistance Management

Palmer amaranth resistant to glyphosate and the acetolactate synthase (ALS)-inhibiting herbicides is widespread throughout the southern United States. This herbicide-resistant biotype is causing substantial crop yield loss, increased management costs, reduction in harvest efficiency, and complete abandonment of many fields. A similar scenario, albeit slower to develop, is underway in much of the Midwest with waterhemp. Opportunities still exist within this region for changes in management practices to avoid extensive resistance and complete loss of glyphosate and other herbicide modes of action. The focus of this presentation will be on Palmer amaranth and waterhemp in regards to their 1) similarities and differences, 2) current and future impact on U.S. agriculture, and 3) rapid evolution of herbicide resistance. Pollen and seed dispersal as a means of gene flow (resistance movement) will be discussed along with best management practices that can be used to mitigate the risks of resistance evolving and spreading. Specific emphasis will be placed on the importance of 1) understanding the biology of resistant-prone weeds, 2) starting clean at planting and staying clean, 3) beginning to scout soon after planting, 4) applying full (lethal) herbicide rates, 5) using multiple efficacious modes of action, 6) emphasizing cultural and mechanical management, 7) preventing weed seed production, 8) preventing field to field and within field movement of weed seed, and 9) developing diversified strategies that focus on reducing the soil seedbank.

Speakers

Jason Norsworthy

University of Arkansas
1366 West Altheimer
Fayetteville, AR 72704
479-575-8740
jnorswor@uark.edu

BIO: Jason Norsworthy is Associate Professor in the Crop, Soil, and Environmental Sciences Department at the University of Arkansas. He teaches Principles of Weed Control and team teaches Colloquium and Integrated Pest Management. He has directed 4 M.S. degrees, 3 Ph.D. degrees, 1 Postdoctoral Associate, and has served on several graduate student committees. Dr. Norsworthy is currently advising 6 M.S. students, 1 Ph.D. student, and 2 Postdoctoral Associates. Jason has authored or co-authored over 100 refereed journal publications and over 350 abstracts. His research has been involved in understanding the evolution and spread of herbicide resistance in Southern cropping systems, specifically cotton, soybean, rice, and corn. His research has centered on developing strategies to manage resistant weeds and reduce the risk of herbicide resistance. Dr. Norsworthy recently led a team in preparing a position paper for the Weed Science Society of America outlining best management practices to mitigate the evolution of herbicide resistance. For his research accomplishments, Jason was awarded the Southern Weed Science Societies' Outstanding Young Weed Scientist award in 2009, and in 2010, he received the Early Career Weed Scientist award from the Weed Science Society of America. In January of this year, the University of Arkansas awarded Dr. Norsworthy and three other weed scientists the John White Team Award for their efforts in research, education, and promotion of herbicide resistance issues relevant to the Midsouth. Most recently, the Arkansas Association of Cooperative Extension Specialists recognized Dr. Norsworthy as Researcher of the Year.

You can catch this session:
Tuesday, December 1, 2009 10:50am - 11:10am