Pasture tolerance and efficacy of three herbicides used against giant buttercup (<i>Ranunculus acris</i> subsp <i>acris </i>L)

Abstract

The herbicides flumetsulam thifensulfuronmethyl and MCPA were compared for their efficacy against giant buttercup (Ranunculus acris subsp acris L) and their damage to perennial ryegrass (Lolium perenne) and white clover (Trifolium repens) The tolerance of perennial ryegrass and white clover to five rates of each herbicide was measured using swards either sown in pots or transplanted from the field The total clover yield harvested over 5 months from newlysown pasture was 80 59 and 4 of the untreated control for flumetsulam thifensulfuronmethyl and MCPA applied at label rates and 95 40 and 30 for transplanted swards respectively The biomass yield of giant buttercup 3 months after treatment was 1 22 and 2 of the untreated control for flumetsulam thifensulfuronmethyl and MCPA applied at the label rate Together these experiments suggest that flumetsulam is the most effective and least pasturedamaging of these three herbicides