Seaweed key to Psa remedy

Chemicals derived from seaweed growing off Mount Maunganui are shaping up as offering a new natural remedy to the kiwifruit vine-killing disease Psa. Photo / John Borren

Chemicals derived from seaweed growing off Mount Maunganui are shaping up as offering a new natural remedy to the kiwifruit vine-killing disease Psa.

Tauranga-based University of Waikato coastal science research graduate Ashleigh Browne has taken a leading role in the work that could result in the patenting of chemicals to boost the vine's immune system.

Professor Chris Battershill, who chairs the university's Coastal Science Unit, said Ms Browne's work held the promise of controlling Psa without loading toxins into the environment.

"We are looking to nature and using the processes that occur naturally in other systems."

Kiwifruit Vine Health chief executive Barry O'Neil said some of the marine compound candidates held promise.

They were extracted from sea life growing around Moturiki (Leisure Island) at Mount Maunganui.

The industry currently used chemicals such as copper and bactericides, chemical agents that helped prevent the formation of bacteria.

However, they were not effective in managing Psa once it got into the vine.

"While we have compounds that kill, we don't have the toolbox for longer-term sustained control so that growers don't have to spray so much - prevention is better than cure."

Mr Battershill said the work aimed to help restore the natural rebalancing that was switched off when the vine was attacked by Psa bacterial pathogens.

The hunt for a new chemical agent had primarily involved seaweeds, with the research showing encouraging preliminary results.

Trials on Psa-infected vines were now being repeated using a different style of biological test in order to track down the exact chemical.

"We need to do that to patent it and scale up production of that molecule."

He stressed there was more work to be done before they could claim to have found another tool to combat Psa.

The next phase of "proving up" the results of trials should be finished by the end of this month. It was too early to say when they would know if they had been successful.