MSc Final Oral Examination: David Westerveld


Interested Members of the University Community are invited to attend the Final Oral Examination for the Degree of Master of Science of David Westerveld off the Department of Plant Agriculture 

Day: Thursday, March 4, 2021
Time: 2:00 PM 

Via Zoom conferencing -
Meeting ID: 998 5344 6084

Passcode: 141824

Thesis Tit​le:  Evaluation of Bromoxynil, Pyraflufen-ethyl/2,4-D, and Tiafenacil for the Control of Glyphosate-resistant Canada fleabane (Conzya canadensis) in Soybean (Glycine max) and Metribuzin for the Control of Waterhemp (Amaranthus tuberuclatus) with Two Mechanisms of Resistance to Photosystem II-inhibiting herbicides

Advisory Committee
Dr. Peter Sikkema, Advisor
Dr. Darren Robinson
Dr. David Hooker

Examination Committee
Dr. Katerina Jordan, Chair
Dr. Peter Sikkema
Dr. Darren Robinson
Dr. Francois Tardif                                     


Fifteen field experiments were conducted in 2019 and 2020 to evaluate bromoxynil, pyraflufen-ethyl/2,4-D, and tiafenacil, alone and tankmixed with metribuzin, for the control of glyphosate-resistant (GR) Canada fleabane applied preplant in soybean. The biologically-effective-dose (BED) of bromoxynil +/- metribuzin, pyraflufen-ethyl/2,4-D +/- metribuzin, and tiafenacil +/- metribuzin was determined. Bromoxynil, pyraflufen-ethyl/2,4-D, and tiafenacil, tankmixed with metribuzin, provided similar control to the current industry standards at 8 weeks after application (WAA). Ten field and eight greenhouse experiments were conducted to evaluate metribuzin, applied preemergence and postemergence, for the control of photosystem II (PS II)-inhibitor resistant waterhemp conferred by target-site resistance (TSR) and non-target-site resistance (NTSR) mechanisms. In both the field and greenhouse studies NTSR PS II-resistant waterhemp was controlled with metribuzin applied PRE and POST, in contrast TSR PS II-resistant waterhemp was not controlled with metribuzin.