Integrating Mechanical and Chemical Control Treatments to Manage Invasive Weed Chromolaena odorata (L.) R. M. King and H. Robinson in Grassland Area

An experiment was conducted on Chromolaena odorata dominated grassland to determine the efficacy of integrated mechanical and chemical control on regrowth of Chromolaena odorata and other weeds and to determine their botanical composition at 30, 60 and 90 days after treatment application. Treatments were spraying of glyphosate (Roundup) onslashed Chromolaena odorata, spraying of glyphosate on normal Chomolaena odorata, spraying of triclopyr (Garlon 4) on slashed Chromolaena odorata and spraying of triclopyr on normal Chromolaena odorata. Efficacy was assessed on the basis of dry weight of weeds yielded at 30, 60and 90 days after herbicide applications. Both herbicides were more effective when sprayed on normal than on slashed Chrmolaena odorata. Regardless of slashing, triclopyr was more effective than glyphosate in suppressing weeds. In glyphosate sprayed plots, Chromolaena odorata and other weeds were the dominant plants, whereas in triclopyr sprayed plots, herbage was the dominant plant, however dominance of Chromolaena odorata progressively increased over time. The results suggest that the interval between slashing and spraying of herbicides is an important factor to determine the efficacy of integrating slashing and herbicide to control Chromolaena odorata.