Weed surveys were conducted in 2014-15 and 2015-16 in 23 rainfed canola fields in Chaouia, semi-arid Morocco, to identify weed flora. A total of 139 weed species were identified. : 91 species in January 2015 and 2016 before in-crop weed control with herbicides and/or hand removal, and 126 species in March 2015 and 2016 after weed control. Weed densities before weed control ranged from 48 to 333 plants m−2 with an average of 152 plants m–², and densities after weed control ranged from 41 to 667 plants m−2 with an average of 115 plants m–². Weeds found after herbicide use and hand removal were a) weeds not controlled or partially controlled by herbicides, b) weeds that emerged after herbicide application, and c) weeds not manually removed after chemical weed control. Research should focus on an integrated weed management strategy based on the use of competitive cultivars, high crop density, preemergence and postemergence herbicides, and mechanical cultivation in canola planted with wide row spacing.
Keywords: Canola, Morocco, weed density, weed frequency, weed relative abundance
