Optimizing Pyroxasulfone Efficacy on Wild Oat (Avena fatua L.)

• Author / Creator

  Mangin, Amy R

• Herbicide resistance in wild oat to current herbicidal mechanisms of action is widespread across western Canada. Pyroxasulfone is a soil-applied very long chain fatty acid inhibitor (Group 15/K3) that has recently been registered in Canada and may become a future tool in managing this resistance, but control of wild oats by pyroxasulfone is inconsistent across various cropping systems. Trials were conducted in controlled conditions to investigate the influence of wild oat seed depth, site of pyroxasulfone interception in wild oat seedling and the downward movement of pyroxasulfone in the soil. Field experiments were then conducted to determine influences and interactions of seed depth, tillage and application timing on control of wild oat by pyroxasulfone. Additionally, resistance screening was used to examine resistance patterns of Canadian wild oat populations to pyroxasulfone and sulfentrazone. It was determined that the pyroxasulfone efficacy on wild oat is influenced greatly by position of the seed in the soil profile relative to the concentrated herbicide layer. Deep-seeded wild oats may be able to avoid herbicidal injury because the location of effective site of herbicide/seedling interception is below the concentrated herbicide layer in the soil. The position of the seed in the soil profile and the soil conditions interacted to influence the control of wild oat by pyroxasulfone in the field. Resistance to pyroxasulfone and sulfentrazone was found in a Canadian wild oat population previously selected for resistance to ACCase-, ALS- and fatty acid biosynthesis inhibitors, which may potentially limit pyroxasulfone and sulfentrazone use in managing herbicide-resistant populations.

• Subjects / Keywords

  • Tillage
  • Wild oat
  • Pyroxasulfone

• Graduation date

  Fall 2016

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R3PV6BJ1R

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.