Evaluation the possibility of reducing Haloxyfop-R-methyl ester (Gallant super®) dose by some vegetable oils in little seed canary grass (Phalaris minor Retz.)

To compare the effects of coconut, sesame and almond oil for increasing the efficacy of Haloxyfop-R-methyl ester herbicide and also reducing the usage dose of herbicide to control little seed canary grass, a greenhouse experiment was performed as factorialbased on completely randomized design with 12 replications in Research greenhouse of Ferdowsi University of Mashhad in 2011. The treatments consisted of herbicide doses at six levels (0, 6.75, 13.5, 27, 54 and 108 g a. i. ha-1) and adjuvant at four levels (without adjuvant, coconut, sesame and almond oil as a vegetable oil at 0.5 percentages by volume. Based on results of the regression analysis and comparison of the mean, all vegetable oils increased Haloxyfop-R-methyl ester herbicide efficacy. The amount of ED50 and relative potency (R) decreased and increased respectively. Data analysis showed that coconut oil increased Haloxyfop-R-methyl ester herbicide efficient more than other vegetables oils. ED50 of coconut oil, sesame seeds, almonds and Haloxyfop-R-methyl ester alone was 29.98, 35.62, 45.93 and 57.80 g a. i. h-1 respectively. Average dry weight for Haloxyfop-R methyl ester, peanut, sesame, coconut oil was 1.65, 1.48, 1.41and 1.12 grams per pot, respectively. It is probably resulted high ratio of saturated to unsaturated fatty acids is reason greater efficiency of coconut oil than other vegetable oils.