Spear grass (Imperata cylindrica, L.) is one of the most serious weed problems facing farmers in the derived savanna zone of Nigeria. The study was designed to evaluate various control methods that would effectively control this noxious weed and increase crop yield in an environmentally sustainable way. The treatments were laid out in a randomized complete block design and these included: Glyphosate only applied at 1.8kg per hectare eight weeks after planting cassava; Glyphosate applied at 1.0kg per hectare eight weeks after planting cassava followed by the planting of Mucuna pruriens; Hand weeding followed by the planting of Mucuna pruriens eight weeks after planting cassava; and Three hand weedings at four, eight and twelve weeks after planting cassava. Analysis of variance (ANOVA) was used to analyse the data. Glyphosate effectively eliminated Imperata shoot both at 1.8kg and 1.0kg active ingredient per hectare but not all the rhizomes were killed. Imperata rhizome dry weight were significantly (P < 0.05) lower in glyphosate plus M. pruriens cover crop (0.5kg/ha) seconded by hand weeding plus M. pruriens cover crop (4.0kg/ha) as against 8.6kg/ha and 25.7kg/kg obtained in glyphosate alone and hand weeding alone, respectively. Cassava tubers and stem yields were significantly (P < 0.05) high in glyphosate applied at 1.0kg/ha plus M. pruriens cover crop (34.9kg/ha and 76.8 bundles/ha respectively). The next significantly (P < 0.05) high yield of cassava tubers and stems (29.5kg/ha and 65.4 bundles/ha respectively) were obtained in glyphosate alone treatment. There was no significant (P > 0.05) difference between Hand weeding plus M. pruriens cover crop and Hand weeding alone in terms of cassava tuber and stem yields. Glyphosate (1.0kg/ha) plus M. pruriens cover crop was recommended as the best method of speargrass (Imperata cylindrica, L.) control.