The weeds if not properly controlled have great ability to settle in agricultural systems, affecting crop production. The objective of this work was to determine the interference and level of economic damage in different density of crop. The treatments were composed of canola hybrids (Hyola 50, Hyola 76, Hyola 433, Hyola 571 CL, Hyola 575 CL and Diamond) and twelve infestation turnip density in crop. The variables evaluated to estimate the competitiveness of the hybrids were plant density, leaf area, soil cover and dry mass of the turnip. Grain yield, canola price, herbicide efficiency, and control cost were used to determine the weed's level of economic damage on the crop. The canola hybrids Hyola 575 CL, Hyola 50, Hyola 76 and Hyola 571 CL are more competitive with turnip. The values of economic damage levels range from 2.86 to 5.95, 2.43 to 5.05, 2.22 to 5.43 and 2.99 to 6.22 turnip plants m-2 for hybrids Hyola 50, Hyola 76, Hyola 571 CL and Hyola 575 CL, respectively, as a function of simulated variables. The increased grain yield, canola price, herbicide efficiency and lower control costs reduce the level of economic damage, justifying the adoption of control.