Chemical control of giant buttercup (Ranunculus acris L.)

Abstract

The effects of single and repeated applications of herbicides on giant buttercup (Ranunculus acris L.) within 1 year, followed in some mstances by further annual applications were examine in two experiments on dairy pastures. Application of MCPA was more effective in August than m May. A single application in August was as effective as split applications in May and August. Further applications of MCPA or MCPB in early December unproved control, except where initial control had been good. The effect of MCPB was slightly less than that of MCPA, although when applied in addition to earlier herbicide treatments differences were small. Application of MCP A at 2- kg/ha was usually slightly more effective than 1 kg/ha. Annualre-treatment with MCPA caused a steady decline in giant buttercup numbers, although giant buttercups were never eliminated even after up to 4 years annual treatment. When spraying was discontinued, buttercup numbers recovered to levels of those in untreated plots in 3 or 4 years. Recovery might have been slower if whole paddocks, instead of small plots, had been treated.

Keywords:

• giant buttercup
• Ranunculus acris
• weeds
• weed control
• herbicides
• MCPA
• MCPB