Effect of Clodinafop-Propargyl and Mesosulfuron-Methyl Herbicides on Wild Oat (Avena ludoviciana) Control under Moisture Stress Condition

In order to investigate the effects of drought stress on the effect of herbicides of Clodinafop-Propargyl (Topic) and Mesosulfuron-methyl (Chevalier) in greenhouse conditions, a split factorial experiment was conducted in 4 replications in a completely randomized design. The main plot consisted of three levels of irrigation (no stress, moderate stress and severe stress) and subplots in a factorial arrangement including 6 doses (0, 25%, 50%, 75%, 100% and 125% of the recommended dose) herbicides Clodinafop-Propargyl (Topic) and Mesosulfuron-methyl (chevalier) in pot. The results of analysis of variance showed that the type of herbicide had no significant difference in the amount of wild oat dry matter and in fact both herbicides had the same effect. However, drought stress had a significant effect on dry weight of oat (P = .05). The mean dry matter of wild oat in treatments without stress, moderate stress and severe stress was 0.50, 0.46 and 0.41 g/plant, respectively. The highest amount of wild oat dry weight was related to control without herbicide treatment or zero dose with mean of 0.96 g/plant, and the lowest was 125% with 0.07 grams per plant. Drought stress reduces the efficiency of herbicides and, by increasing the dose of herbicide from the recommended amount, this defect can be eliminated. In this experiment, with a 25% increase in dosage of herbicides, their efficacy was similar to that in the recommended dosage in non-stress conditions.