Submitted to: North Central Weed Science Society US Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 11/21/2010
Publication Date: 12/13/2010
Citation: Liu, J., Davis, A.S., Tranel, P. 2010. Modeling the spread of glyphosate-resistant common waterhemp [abstract]. North Central Weed Science Society Abstracts. 65:59. Interpretive Summary:
Technical Abstract: Glyphosate-resistant (GR) waterhemp is posing a serious threat to crop production in the Midwest. Knowledge of how GR waterhemp spreads within and among fields is needed for risk assessment and to fine-tune weed management strategies. In this study, we tracked the spread of GR waterhemp at both local and landscape levels. Also, a field experiment was conducted to determine pollen dispersal dynamics. In three years (2006-2009), GR waterhemp appears to have expanded from a small origin population, at the field scale, to a county wide spatial distribution, as far as 40 km or more. Integro-difference equations were used to model the movement of the GR trait, in which pollen mediated gene flow was assumed as the major means of GR spread. Based on this, the invasion wave was estimated to move less than 20 km in four years assuming the maximum wind speed at 10 m/s. To obtain the observed levels of movement, a very long-distance dispersal factor besides wind must be at play. It is concluded that independent selection events of GR waterhemp and/or long distance dispersal mediated by e.g., farm equipment play an important role in assisting the evolution and spread of GR waterhemp.