کاربرد کلروتولورون+ ایزوکسابن و کلروتولورون+ دیفلوفنیکان در گندم جهت کنترل چچم، یولاف وحشی زمستانه و فالاریس مقاوم به علف‌کش

Consecutive application of herbicides has led to herbicide resistance in weeds and reduced efficacy of herbicides. Noting the significance of Golestan province in wheat production in Iran and ever-increasing reports concerning herbicide resistance in the province, it is essential to introduce new herbicides to manage herbicide resistance without negatively affecting wheat. Thus, the efficacy of new herbicides chlorotoluron+ isoxaben and chlorotoluron+ diflufenican in controlling herbicide-susceptible and -resistant biotypes of rigid ryegrass (Lolium rigidum), winter wild oat (Avena ludoviciana) and short-spiked canarygrass (Phalaris minor) and their effect on wheat was investigated during 2022-2023 at Gorgan University of Agricultural Sciences and Natural Resources. Acetyl CoA carboxylase (ACCase)- resistant and -susceptible seeds of the mentioned weeds alongside wheat were sown in pots under greenhouse conditions. Then, the pots were sprayed with various rates of chlorotoluron+ isoxaben and chlorotoluron+ diflufenican pre-emergence herbicides with three replicates. Four weeks after spraying, the dry weight of weeds and wheat was measured and compared with the untreated control. A three-parameter log-logistic model was fitted to the data for analysis. The results showed that the studied herbicides had no phytotoxicity on wheat. Application of chlorotoluron+ diflufenican at 340.62 and 331.44 g a.i ha-1 controlled 50% (ED50) of resistant and susceptible biotypes of winter wild oat. The ED50 value for resistant and susceptible biotypes of phalaris was 334.75 and 294.82 and for ryegrass was 377.66 and 356.26 g a.i ha-1, respectively. Furthermore, the dose required for 50% reduction in dry weight (ED90) for susceptible and resistant biotypes of winter wild oat, phalaris and ryegrass for this herbicide was 1972.67 and 1969.84, 1918.57 and 2038.85, and 1932.69 and 2114.93 g a.i ha-1, respectively (no significant differences). The ED50 value for susceptible and resistant biotypes of winter wild oat, phalaris and ryegrass treated with chlorotoluron+ isoxaben was 290.94 and 311.38, 259.11 and 283.33, and 280.71 and 307.00 g a.i ha-1, respectively. Application of this herbicide at 1634.21 and 1478.34 g a.i ha-1 reduced the dry weight of resistant and susceptible ryegrass biotypes by 90%, respectively. Also, ED90 value for resistant and susceptible biotypes of winter wild oat was 1731.63 and 1712.26 and for phalaris was 1832.88 and 1754.07 g a.i ha-1 (no significant differences). Application of new herbicides chlorotoluron+ isoxaben and chlorotoluron+ diflufenican at their recommended rate controlled herbicide- susceptible and -resistant biotypes of ryegrass, winter wild oat, and phalaris. Thus, these herbicides are recommended to manage herbicide resistance in wheat fields of Golestan province.