MSc Final Oral Examination: Nicole Langdon


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

Date:Thursday, April 9th ,
Time: 1:30 PM

Delivered via Zoom

Please contact if you wish to be added to the contact list for the Zoom conference.

Thesis Title: Evaluation of the Fit of Tolpyralate For Weed Management in Field Corn (Zea Mays L.) in Ontario.

Advisory Committee                          Examination Committee 

Dr. Peter Sikkema, Advisor                 Dr. Gopi Paliyath, Chair

Dr. Darren Robinson                            Dr. Peter Sikkema

Dr. David Hooker                                  Dr. Darren Robinson

Dr. Alan Raedar                                    Dr. François Tardif


Thirty-six field experiments were conducted over a two-year period (2018, 2019) to evaluate the fit of tolpyralate, a newly registered benzoylpyrazole 4-hydroxyphenyl-pyruvate dioxygenase inhibitor, for weed management in corn in Ontario. The importance of adjuvants (methylated seed oil (MSO) concentrate and urea ammonia nitrate (UAN)) with tolpyralate + atrazine and the influence of Roundup Weathermax® was determined for control of nine common annual weed species, glyphosate-resistant (GR) Canada fleabane and GR waterhemp. Generally, optimal control was achieved with tolpyralate + atrazine + MSO and when tolpyralate + atrazine was co-applied with Roundup Weathermax®, there was no further increase in weed control from the addition of MSO or UAN. Tolpyralate and tolpyralate + atrazine has residual activity on GR Canada fleabane, comparable to current industry standards. Three weed species exhibited a slight quadratic time-of-day (TOD) effect to tolpyralate + atrazine, although, consistent control was achieved regardless of application time. Corn injury was greatest from tolpyralate + atrazine when applied at the 2X rate alone and/or co-applied with glyphosate at 1 WAA. There was no increase in corn injury when tolpyralate + atrazine was co-applied with a commercial glyphosate formulation and yield was not impacted. These results provide useful information for use of tolpyralate in a corn production system.