Time-of-day effect on weed control efficacy with tolpyralate plus atrazine

Abstract

Tolpyralate is a new 4-hydroxyphenyl-pyruvate dioxygenase (HPPD)-inhibiting herbicide for weed control in corn. Previous research has reported efficacy of tolpyralate + atrazine on several annual grass and broadleaf weed species; however, no studies have evaluated weed control of tolpyralate + atrazine depending on time-of-day (TOD) of application. Six field experiments were conducted over a two-year period (2018, 2019) near Ridgetown, ON to determine if there is an effect of TOD of application on tolpyralate + atrazine efficacy on common annual grass and broadleaf weeds. An application was made at three-hour intervals beginning at 06:00 h and the last application at 24:00 h. There was a slight TOD effect on velvetleaf, pigweed species and common ragweed control with tolpyralate + atrazine; however, the magnitude of change throughout the day was ≤3% at 2, 4 or 8 WAA. There was no effect of TOD of tolpyralate + atrazine on the control of lambsquarters, barnyardgrass and green foxtail. All weed species were controlled ≥88% 8 WAA. There was no effect of TOD of tolpyralate + atrazine application on corn yield. Results of this study show no evidence of a TOD effect on weed control efficacy with tolpyralate + atrazine.

Interaction between 4-hydroxyphenylpyruvate dioxygenase–inhibiting and reactive oxygen species–generating herbicides for the control of annual weed species in corn

“…Herbicide efficacy of atrazine, bromoxynil, bentazon, and glufosinate can be affected by the time of day of application (Doran and Andersen 1976;Montgomery et al 2017;Stewart et al 2009). In contrast, a lack of time of day of application effect on tolpyralate þ atrazine efficacy has been reported for the control of several of the weed species investigated in this study (Langdon et al 2021). Therefore, all herbicide treatments were applied within the period of 0900 to 1030 hours Eastern Daylight Saving Time to have consistent data among site-years.…”

Growth, development, and chlorophyll indexes of glyphosate and glufosinate-tolerant maize under herbicide application

“…For maize, as alternative herbicides or as a complement to glyphosate, atrazine (mechanism of action of PSII inhibitors) can be highlighted. It can be applied in the pre-or post-emergence of the crop, with an effect on eudicotyledonous weeds in pre-emergence or post-initial (Barnes et al, 2020;Langdon et al, 2021); and it is selective for maize (Giovanelli et al, 2018). Araújo et al (2021) do not observe reductions in yield or 100-grain weight or changes in nutrient contents, even with the use of high rates of glyphosate and glufosinate in RR2/ LL maize.…”

Impact of climate changes on weed vegetation and herbicides efficiency

“…Отримані результати підтвердили значний видоспецифічний вплив температури навколишнього повітря, інтенсивності освітлення та орієнтації листків на ефективність післясходових гербіцидів [99]. Водночас для нового гербіциду інгібітора 4-гідроксифенілпіруватдегідрогенази (HPPD) толпіралату, застосованого разом із атразином у посіві кукурудзи, не виявлено залежності ефективності від часу внесення протягом доби [101].…”