Response of Wild Oat (Avena fatua), Flax (Linum usitatissimum), and Rapeseed (Brassica campestrisandB. napus)to Diclofop-methyl

Abstract

Diclofop-methyl {methyl ester of 2-[4-(2,4-dichlorophenoxy)phenoxy] propanoic acid} applied as postemergence treatment at rates of 0.84 to 1.68 kg/ha controlled 65 to 87% of the wild oat (Avena fatuaL.) without injuring flax (Linum usitatissimumL.) or rapeseed (Brassica campestrisL. andB. napusL.) Yields of both crops were significantly increased because wild oat competition was minimized. Wild oat control was further improved when adjuvants were added with the herbicide at a concentration of 0.5% (v/v) to the spray mixture. Oil content, iodine number, and linolenic acid concentration of flax, and oil content of rapeseed were increased with the application of the herbicide, while the protein content of meal from both crops was unaffected. When flax was grown in the greenhouse under weed-free conditions, the 0.84 and 1.12 kg/ha rates of the herbicide did not affect seed and oil composition, whereas the 1.68 kg/ha rate decreased protein content, and slightly increased oil content, but had no significant effect on iodine number when compared with the untreated check. The change in seed and oil quality of flax appears to be related to a reduction in weed competition by the herbicide.