Giant buttercup (Ranunculus acris L.) is estimated to cost the New Zealand dairy industry $118 million annually in lost milksolid production opportunity through the exclusion of palatable pasture species. Historical reliance by dairy farmers on annual or biennial applications of the 'phenoxy' herbicides MCPA and MCPB, has led to the widespread evolution of phenoxy-herbicide-resistant populations of the weed. The newer herbicides, thifensulfuron methyl and flumetsulam are now being used against giant buttercup, although thifensuluron, like MCPA, can cause clover damage and as a result may promote the growth of giant buttercup populations. In this paper we review the history of giant buttercup management on New Zealand dairy farms and the science that led to the discovery of the herbicide resistance. We also attempt to define a path toward sustainable ecologically-based management of this weed based upon an improved understanding of its population dynamics and the use of a pasture-selective mycoherbicide utilizing the naturally-occurring fungus, Sclerotinia sclerotiorum. Keywords: dairy pasture, economics, giant buttercup, herbicide resistance, mycoherbicide, opportunity cost, population dynamics, Ranunculus acris, weed
Understanding population dynamics of a numerically dominant species at hydrothermal vents: a matrix modeling approach
