Optimizing the Performance of Clethodim and Haloxyfop-R-Methyl Ester Herbicides on Barnyardgrass (Echinochloa crus-galli L.) Control by Citogate and Turnip Vegetable Oil

In order to evaluate the potential of citogate and turnip vegetable oil in increasing the performance of barnyardgrass (Echinochloa crus-galli) control by colthodim and haloxyfop-r-methyl ester herbicides, two greenhouse experiments were carried out in the Research Greenhouse of the Faculty of Agriculture, Birjand, Iran, in 2016; this study was based on a factorial arrangement as a completely randomized design with three replications. Treatments in each experiment included herbicide concentrations at seven levels (0, 6.25, 12.5, 25, 50, 75, and 100% of the recommended dose) and additives were applied at three levels (turnip oil, citogate, and without additives). The application of additives with colthodim herbicide on barnyardgrass (based on the shoot dry weight) led to 4.5% and 5.4% decreases in ED50 in the presence of turnip oil and citogate, respectively. Based on the root dry weight, ED50 was reduced to 22.9% and 21.6% in the presence of turnip oil and citogate, respectively. The results of the use of additives with Haloxyfop-r-methyl ester also showed a similar trend. However, the increase in the efficiency of Haloxyfop-r-methyl ester was higher than that of colthodim herbicide. The Haloxyfop-r-methyl ester ED50 values for the shoot dry weight of barnyardgrass were reduced by 14% and 16.3% in the presence of turnip oil and citogate, respectively. The Haloxyfop-r-methyl ester ED50 values for the root dry weight in the presence of turnip oil and citogate were 10 and 7 times higher than those in the treatments without additives, respectively. According to the results of this study, application of appropriate additives may lead to decrease in the extent of herbicide contamination of soil and water resources.