Farmers keen to collaborate on Cali control

Farmers from across the country have jumped on board a unique programme designed to help them eliminate one of their most expensive and persistent weeds. 

An example of the problems faced by farmers involved in the programme.

They’re now getting expert guidance and support on successful Californian thistle control thanks to a collaboration between Corteva Agriscience and PGG Wrightson.

It’s a team effort that will last for at least 18 months, and results and progress are being shared with anyone interested in best practice eradication of a widespread weed that doesn’t discriminate between regions, or types of farm system. 

Glen Surgenor, Corteva marketing manager, says the fact that farmers from Southland to Waikato have joined the programme reinforces both the scale of the problem, and the opportunity to remedy it. 

“We’re really pleased to have such a broad representation of different regions and growing conditions.”

With the first Tordon PastureBoss spray at hard ball stage in early summer now under their belts, the focus for farmers involved has turned to the all-important autumn follow-up with Grassmaster MCPA  herbicide. 

That will be followed in summer 2025 with a spot spray of Tordon PastureBoss where needed to kill any remaining plants. 

Surgenor says farmers have been excited by their results so far, but the mark of success will be how happy they are in a year’s time. 

A critical part of the partnership is a digital portal where farmers can easily record their herbicide applications and access technical information. 

“We want to document and share what happens on these farms as they go through the programme, to show that Californian thistle can be effectively managed when a program is followed,” Surgenor says. 

Corteva has added a page about the project to its NZ website so anyone can follow its progress. 

Joining forces with a partner like PGG Wrightson for best practice demonstration like this is a first for Corteva, and a win:win for all involved, he says. 

“We know the issue is getting worse; California thistles are spreading and the feedback we’ve been getting is that farmers are becoming disillusioned and losing confidence in their ability to stay on top of them.  

“We also realise one of the best ways to promote what can be achieved with a programmed approach control is through using demo sites, and sharing farm case studies. 

“But we’re a small team, and we alone don’t have the resources to do this type of extension work at scale, so it made perfect sense to partner with PGG Wrightson on a multi-year national initiative we believe will make a real difference to farmers.”

Tordon PastureBoss is the premium herbicide to use at the front end of a control programme, especially for dense infestations. 

The withholding periods are relatively short (three days for milk; seven days for meat) and although it will damage clover, pasture production and grazing is already much reduced where thistle populations are high, and that ground will be re-gained at the completion of the programme. 

But if your farmers didn’t get an application on before Christmas, when thistles were at hard ball stage, Surgenor says they can still get their own programme underway this autumn, using Tordon PastureBoss as the first spray.