The control of Achillea millefolium in the Snowy Mountains of Australia

Abstract

The response of Achillea millefolium L. to herbicides was measured to determine the effectiveness of the current recommendations and to test alternative herbicides. Five plots at each of the three replicate sites were selected and randomly treated with one of the four herbicides: dicamba/2,4-D, glyphosate, metsulfuron-methyl and triclopyr/picloram. After 12 months, the recommended treatment, dicamba/2,4-D, did not cause a significant reduction in aerial biomass compared with untreated controls and the number of flowering stems was significantly increased in treated plots. Metsulfuron-methyl and triclopyr/picloram caused a significant reduction in A. millefolium aerial biomass but did not affect the number of flowering stems. Glyphosate produced a significant reduction in aerial biomass and was less effective. These results suggest that the current recommendation for A. millefolium might be improved. Site-specific effects such as aspect may also influence the effectiveness of herbicides on this species.