Clover root weevil group offer management advice

Clover root weevil (CRW) is silently eating profitability under NZ pastures and farmers must have answers for this scourge, an action group urges reports Country-wide. The NZ Clover Root Weevil Action Group has instigated research and published recommendations for the on-farm management of pasture clover in the presence of CRW. The findings and recommenda­tions have relevance to farmers in regions where bio-control of CRW is not working or in years when it is less effective, and to regions where CRW is establishing for the first time. The Irish parasitic wasp Microctonus ("little murderer") aethiopoides, is being distributed throughout the country and can help to control CRW numbers. But its impact is affected by both environmental conditions and pasture management. In Northland, the parasitic wasp has not established, although in regions further south it has established and is spreading rapidly. However, even if the wasp is present, how effective it is at controlling the weevil appears to depend on how well pasture clover is managed. Fortunately, the action group has been actively looking for farm management responses to CRW infestation alongside implementation of the bio-control programme. It obtained funding from MAF's Sustainable Farming Fund and from AGMARDT, over the past four years, and recently drew together the findings of commissioned research work. Just how big a problem is CRW?  A review of the studies on the impact of CRW on white clover drymatter production has shown that losses over the medium term were generally in the range from 18-35%. If a "do nothing" approach is adopted, the weevil could potentially cost the pastoral economy around $400 million a year.