Feilding-Rangitikei Herald

Columns
Thursday, April 27, 2017

It's great when a group of likeminded, determined and informed individuals facilitate a solution to a problem.

It was recently announced that the Rangitikei Horsetail Control Group has been granted a further $174,000 from the Sustainable Farming Fund to mass-rear horsetail weevils.

Over the past seven years or so this group has been instrumental in developing a strategy to control and destroy horsetail, which is a fern-like plant native to North America and Eurasia that has become a serious invasive pest, particularly in the Rangitikei.

This latest round of funding will allow the Rangitikei Horsetail Control Group, in a project run by Lindsay Smith of Landcare Research based at Lincoln University, to mass-rear horsetail weevils.

Then, with community involvement and consultation, they will be control-released in infested areas over the coming years; while data will be collected at release sites to allow the impact of the weevils to be evaluated.

It's a great result for a team of people and a project that has been several years in the making.

Alistair Robertson is Chair of the Rangitikei Horsetail Control Group (RHCG), which he helped set up in about 2010 in response to serious concerns about the spread of this invasive plant.

The Rangitikei Horsetail Control Group organised several field days throughout our region between 2013 and 2015. Their primary focus was information sharing, discussing risks and teaching people how to manage this weed. They also talked about research and expected outcomes as a result of the work being undertaken by their group, as it was becoming clear that traditional measures were costly and failing to control or reduce the spread of the weed.

The RHCG's first approach to the Sustainable Farming Fund was in 2015 for capital to run a three-year trial programme investigating the introduction of biocontrol agents to tackle the escalating problem of horsetail weed. Their proposal, which was submitted in conjunction with Alastair Cole from the Landcare Trust, Craig Davies, the Environmental Co-ordinator at Horizons and Lindsay Smith of Landcare Research, who was responsible for conducting the clinical trials, was successful.

Initially horsetail was grown in a controlled environment at Lincoln University and both horsetail weevils and sawflies, which had been imported from the northern hemisphere, were introduced to test their effect on the plant's life cycle. It was eventually determined that the weevil was the most effective biocontrol agent.

After the Lincoln-based clinical trial the next step for the RHCG was to apply to the Environmental Protection Agency for permission to release the weevils. A planned release date of November 2017 was delayed due to an insufficient adult population being collected from the trial process.

Horsetail poses a genuine threat to sheep and cattle grazing.

Its high silica content wears the animals' teeth away. It is also potentially toxic if cut and dried with grass to make hay.

Biocontrol offers a cost-effective and enduring solution to a very real and escalating environmental and pastoral farming issue. And it's a great example of how with a coordinated and professional approach, it is possible to make a real difference. I'd like to take this opportunity to congratulate the Rangitikei Horsetail Control Group and all those involved.