{"id":14922,"date":"2015-07-30T00:00:00","date_gmt":"2015-07-29T12:00:00","guid":{"rendered":"https:\/\/www.farmersweekly.co.nz\/war-of-the-roses\/"},"modified":"2015-07-30T00:00:00","modified_gmt":"2015-07-29T12:00:00","slug":"war-of-the-roses","status":"publish","type":"post","link":"https:\/\/www.farmersweekly.co.nz\/news\/war-of-the-roses\/","title":{"rendered":"War of the Roses"},"content":{"rendered":"Reading Time: <\/span> 2<\/span> minutes<\/span><\/span>

Giant buttercup is estimated to cost\u00a0farmers on average about $1000 a hectare\u00a0each year in lost production and sprays,\u00a0which Rose equates to $85,000 for his\u00a0farm. He says that\u2019s \u201cpretty signifi cant\u201d\u00a0for a small family farm.<\/p>\n

Cows avoid the toxic leaves leaving\u00a0the plants well alone to dominate the\u00a0surrounding grass struggling beneath\u00a0it. Herbicides knock it back but Rose\u00a0says they also hammer the pasture by as\u00a0much as 30% for a couple of months that\u00a0would usually be the peak growth period\u00a0on a dairy farm.<\/p>\n

This means he doesn\u2019t\u00a0have the surplus growth for supplements\u00a0and there\u2019s the problem of resistance.\u00a0The emerging resistance to herbicides\u00a0in giant buttercup prompted the three year\u00a0project that includes AgResearch\u00a0field trials in Golden Bay. Though there\u2019s\u00a0a range of different herbicide products on\u00a0the market to fight giant buttercup they\u00a0span only four modes of action (MOA)\u00a0which means farmers need to know the\u00a0MOA in each herbicide and rotate the\u00a0MOA each year to avoid resistance.<\/p>\n

\u201cGiant buttercup has a very waxy\u00a0coat which is genetically different to the\u00a0buttercup it used to be,\u201d Rose says.<\/p>\n

\u201cIt has evolved to become more\u00a0resistant and if we can kill half the\u00a0buttercup in the paddock after a spray\u00a0I\u2019m happy now.\u201d<\/p>\n

The farm carries the 230-cow herd\u00a0through winter and while grasses are\u00a0destroyed in the mud the giant buttercup\u00a0rhizome stays intact to dominate\u00a0regrowth in the paddock.<\/p>\n

In the past Rose says droughts knocked\u00a0the buttercup back each year and kept\u00a0some control over it but irrigation\u00a0installed to boost production also boosts\u00a0buttercup growth year-round.<\/p>\n

\u201cThese days you really have to\u00a0spray every year and that\u2019s really not\u00a0sustainable so we\u2019re keen on alternatives\u00a0being developed.\u201d<\/p>\n

Taking action<\/h2>\n

Once a giant buttercup has evolved resistance to a particular mode of action (MOA)\u00a0none of the herbicides with that MOA \u2013 such as MCPA and MCPB \u2013 will have an effect\u00a0on the weed, AgResearch scientist Graeme Bourdot says. His research shows buttercup\u00a0populations that have become resistant to MCPA and MCPB will take about 28 years to\u00a0become susceptible again. And the regression back to susceptibility would happen only if\u00a0the farmer stopped using those herbicides.<\/p>\n

If farmers are rotating sprays annually through the four available MOAs they will use the\u00a0same MOA only every fi fth year. If they sprayed buttercup every second year MOA rotation\u00a0could allow them to use the same MOA once every nine years and Bourdot says resistance\u00a0would be very unlikely.<\/p>\n

Information on the MOAs and giant buttercup control is available at the new AgPest site\u00a0(formerly PestWeb) at www.agpest.co.nz and results from the Golden Bay trials will be\u00a0updated on to this website as the three-year trial progresses.<\/p>\n

The project is cash-funded by the Sustainable Farming Fund, DairyNZ and Ravensdown\u00a0with in-kind funding from Dow AgroSciences, the Taranaki and Southland regional councils\u00a0plus Tasman District Council.<\/p>\n","protected":false},"excerpt":{"rendered":"Giant buttercup has plagued David Rose\u2019s\u00a0dairy farm in Golden Bay for decades and\u00a0has built-up resistance to herbicides but\u00a0field trials in his paddocks show pre-graze\u00a0mowing may be a handy tool to squash\u00a0the invasive weed.\u00a0The 85ha family farm on the edge\u00a0of Takaka is ideal for the trials with\u00a0buttercup liberally sprinkled through the\u00a0paddocks. In the past, 50% of the pasture\u00a0cover was giant buttercup and when the\u00a0bull paddock was left out of the spray\u00a0regime for four years it soared to 90% of\u00a0the cover.\n","protected":false},"author":33,"featured_media":14923,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_FSMCFIC_featured_image_caption":"","_FSMCFIC_featured_image_nocaption":"","_FSMCFIC_featured_image_hide":"","footnotes":""},"categories":[3],"tags":[],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t