Greencollar NZ & Agri Automation trial UV light to sustainably tackle powdery mildew on grape vines

Powdery mildew, which studies indicate is becoming increasingly resistant to chemical weapons, is one of the most vexing problems for grape growers. The fungal pathogen attacks grape vines, growing on young, green tissue, including leaves, shoots and, critically, the developing grape berries. Untreated, it can stunt berry development and cause skin discolouring.

While promising UV-C technology trials are well underway in the wine grape industry across New Zealand and Australia, applying the innovation to table grapes is a first. Treating table grapes adds critical complexity given the potential for the UV to give the berries 'sunburn'. Unlike wine grapes, where minor imperfections can be acceptable, table grapes must be perfect to meet market expectations. This makes the precision and timing of disease control crucial.

At Greencollar NZ, taking up the challenge to find a sustainable solution for this problem aligns perfectly with the company's commitment to environmental stewardship and sustainable innovation. Its other sustainable initiatives include using New Zealand wool for packaging and EV carts for vineyard work.

"This trial represents a significant step in our journey toward more sustainable farming practices," says Greencollar chief executive Shin Koizumi.

"We're constantly seeking solutions that can reduce our environmental footprint while maintaining the premium quality our markets demand. UV-C technology could be transformative for table grape production."

Agri Automation is a precision agricultural and robotics company focused on developing innovative technology for farmers and orchardists. It has UV-C unit trials running on wine grapes in Marlborough, and is not turning its attention to other applications - in  this instance, table grapes.

While the wine grape trials are using automated units with table grapes "we're not there yet", says Agri Automation managing director Chris Clifford.

"While technically it is the same fruit, the precision we need for table grapes is much greater. The trial rig we use at Greencollar will help us gather the data that we need for proof of concept to move onto the next iteration - automation."

The Greencollar trial uses a manual prototype - quite a commitment by the company as it requires the team to move it around the vines at night, when research shows the fungi are most vulnerable to UV-induced DNA damage.

"The biggest challenge with UV-C technology is the night-time application requirement," says Mr Clifford. "Long-term, that's not cost effective or practical for an operation of any size if you're relying on manual operation. Our goal is to make this technology practically feasible through automation."

For Greencollar, the benefits extend beyond disease control. The trial aligns perfectly with its sustainability initiatives by offering:

• Significant reduction in chemical applications
• Ability to treat during adverse weather conditions
• Reduced environmental impact
• Potential for extended treatment windows closer to harvest with no withholding period.

As the trial progresses, Greencollar is carefully monitoring disease control efficacy and aesthetic impacts on the fruit. The goal is to develop application protocols that maintain their high visual standards while delivering effective disease control.

"This technology represents the kind of innovation we need in modern agriculture," says Koizumi.

"It's about finding solutions that work for both business and the environment."