Led by Bragato Research Institute in partnership with A Lighter Touch, a new project aims to see if UV-C light can be used in place of traditional fungicides on vineyards. Photo: Supplied
A trial involving robots fitted with UV light panels aims to give grape growers a new alternative to fungicides.
Currently underway, the project will involve two years of trials at a Marlborough vineyard growing sauvignon blanc, starting from budburst through to harvest. The variety grows quite dense canopies which can leave them especially prone to the fungal disease.
Led by Bragato Research Institute in partnership with A Lighter Touch, the research project aims to see if UV-C light can be used to control powdery mildew in place of traditional fungicides.
The trial involves an automated machine emitting different frequencies of UV-C light across different rows at night.
Bragato's research and extension specialist Dr Paul Epee said the process is most effective at night as it prevents the fungus pathogen from regenerating.
"The technology emits UV radiation at an intensity that can damage the DNA of the pathogens and we apply this UV light treatment at night because during the day those pathogens can easily repair the damage to their DNA because sunlight allows them to repair their DNA. That mechanism is inactive at night."
The trial involves an automated machine emitting different frequencies of UV-C light across different rows at night - applying the uv radiation at night prevents the fungus pathogen from regenerating. Photo: Supplied
Epee said there were a number of benefits to using UV-C light over traditional fungicides currently used in vineyards, which can pose a number of issues. This includes harmful residues impacting wine quality, fungicide resistance and declining soil health and biodiversity.
He said UV light was more "environmentally friendly" and a "good alternative in controlling powdery mildew".
"UV light does not accumulate in the soil or in the environment and therefore has little negative effects on the microbial diversity. UV light does not leave toxic residues on grape."
The UV light panels are fitted to existing viticulture machinery which are lighter - reducing soil compaction - and are powered electrically, making them more sustainable.
"The technology can also be operated remotely and autonomously," Epee said, adding this could also reduce labour costs.
Technical viticultural specialist Chris Ireland said the aim of the trial is to see if UV works well in isolation or even as a combination to help reduce fungicide use. The use of UV-C light technology will be assessed against a standard spray programme also being monitored.
Ireland said they were effectively running two trials - testing how frequently they needed to apply the UV treatment for it to be effective and seeing if growers could reduce fungicide use in their spray programmes by 50% through supplementary UV treatments.
"We are trying to take away some of the sprays that might be going on, putting UV into the traditional sauvignon vineyard and seeing how that compares to the conventional sort of spray programmes."
A Lighter Touch has a similar project underway with Summerfruit New Zealand, with trials underway on a cherry orchard in Cromwell using the technology as a control for brown rot and bacterial canker.
