Optimizing the Performance of Imazethapyr in Barnyardgrass (Echinochloa crus-galli Beauv) Control by Vegetable Oils Adjuvants

To study the effects of vegetable oils on the performance of Imazethapyr (a herbicide with a relatively high amount of residue in the soil and environment) in barnyardgrass (Echinochloa crus-galli Beauv) control, a factorial experiment based on completely randomized design with four replications was conducted in the Research Greenhouse of College of Agriculture, Birjand University, Birjand, Iran in 2016. The treatments consisted of Imazethapyr concentration at six levels (0, 6.25, 12.5, 25, 50, and 100 g ai ha-1) and adjuvant at 6 levels (with and without Coconut, Peanut, Turnip, Bitter almond and Castor oils). The results of this study revealed that the concentration of herbicide, the type of adjuvants and the interaction between concentration and adjuvants were significant on all measured traits including height, fresh and dry weight of the shoot and root, root volume and root length. Castor oil and coconut oil showed the highest and lowest potential in improving the efficacy of Imazethapyr. In the presence of vegetable oils, the ED50 values required for the traits of shoot and root fresh weight were decreased significantly compared to the dry weight of the shoot and root. Relative potency values showed that using any of the vegetable oils could reduce the amount of herbicide needed to control the E. crus-galli. Due to the lessened reduction in measured traits in the presence of vegetable oil treatments, using these additives has the potency to reduce the entry of Imazethapyr herbicide to the environment.