Author(s)

Nicole M. Langdon, Nader Soltani^1*, Alan J. Raedar², David C. Hooker¹, Darren E. Robinson¹, Peter H. Sikkema¹

University of Guelph Ridgetown Campus, Ridgetown, Canada.
University of Guelph Ridgetown Campus, Ridgetown, Canada.
ISK Biosciences Inc., Concord, OH, USA.

Tolpyralate is a new benzoylpyrazole herbicide for weed management in corn. It is recommended to be co-applied with atrazine along with the adjuvants methylated seed oil concentrate (MSO) plus an ammonium nitrogen fertilizer, such as urea ammonium nitrate (UAN). Two studies were conducted on glyphosate-resistant (GR) Canada fleabane and GR waterhemp to determine if an additional adjuvant is still required when tolpyralate plus atrazine are tankmixed with a commercial glyphosate formulation (Roundup WeatherMAX^®) in corn. Trials were conducted over a two-year period (2018-19) on farms in south western Ontario with confirmed GR populations. When co-applied with Roundup WeatherMAX^®, the addition of MSO to tolpyralate + atrazine increased control of GR waterhemp 9%; however, there was no increase in GR Canada fleabane control from the addition of additional adjuvants. At 8 WAA, all treatments provided > 91% and > 84% control of GR waterhemp and GR Canada fleabane, respectively. This study concludes that the addition of Roundup WeatherMAX^® to tolpyralate plus atrazine improves the control of GR waterhemp and GR Canada fleabane in corn.

Biomass, Crop Injury, Density, Sensitivity, Weed Control, Yield, Amaranthus tuberculatus, Conyza canadensis L. Cronq

Langdon, N. , Soltani, N. , Raedar, A. , Hooker, D. , Robinson, D. and Sikkema, P. (2020) Influence of Adjuvants on the Control of Glyphosate-Resistant Canada Fleabane and Waterhemp in Corn with Tolpyralate. American Journal of Plant Sciences, 11, 354-371. doi: 10.4236/ajps.2020.113026.