Review on ecology and control of Achillea millefolium L. (yarrow) on arable land in New Zealand

Abstract Achillea millefolium L. (yarrow), a perennial competitive ruderal, has become an increasing problem on arable land in New Zealand as a result of reduced cultivation, horticultural development, and the ineffectiveness of herbicides. Research conducted mainly in Canterbury, on aspects of the seed and rhizome biology of A. millefolium, is considered in relation to its control. It is concluded that major difficulties still exist in the selective control of this weed in crops. Strategic cultivations during pre-sowing fallows and the use of glyphosate and clopyralid as broadcast or directed treatments are the best control options.