Thursday, April 25, 2024

Psa laid low by bio-pesticide

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Taking care of diseases using microorganisms is the simple basis of bio-control crop treatments and one that has earned Plant & Food Research, Zespri and UPL a finals spot in this year’s KiwiNet Research Commercialisation awards. Plant & Food Research commercialisation manager Greg Pringle spoke to Richard Rennie about the emerging field of bio-control and its potential. Born out of the post-Psa flurry of research, the bio-control product AureoGold has provided a win-win outcome for the industry and growers as a means to control the insidious creep of the disease.
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Taking care of diseases using microorganisms is the simple basis of bio-control crop treatments and one that has earned Plant & Food Research, Zespri and UPL a finals spot in this year’s KiwiNet Research Commercialisation awards. Plant & Food Research commercialisation manager Greg Pringle spoke to Richard Rennie about the emerging field of bio-control and its potential.

Born out of the post-Psa flurry of research, the bio-control product AureoGold has provided a win-win outcome for the industry and growers as a means to control the insidious creep of the disease.

The conception of the bio-control product came as the kiwifruit industry and Plant & Food Research threw intense resources into helping stave off a disease that threatened to wipe out the country’s highest value horticultural crop in late 2010.

“We had a lot going on, it was all hands on deck across the research sector, we needed a range of options to control Psa,” Plant & Food Research commercialisation manager Greg Pringle says. 

While there were conventional synthetic crop treatments on the market that had some success in Psa control, there were issues with residues that would be problematic for maintaining NZ’s reputation for high quality, low residue kiwifruit.

“Generally one of the benefits of a bio-control product is that you are not as limited by residues.”

Researchers looked early on at bio-control approaches, or treatments that at their core have a living organism whose actions control the targeted disease.

“As a sector bio-controls are experiencing significant global growth, as much as four times the growth rate of conventional crop treatments. All major agrichemical companies are now devoting significant research to this field,” Pringle says. 

But in looking for a biological answer to a biological problem, scientists have a number of hurdles to clear.

“The final product has to be capable of being ‘grown’ in commercial quantities to be used, it has to have compatibility with other treatments, it has to be capable of being mixed, sprayed and applied to the surface of the crop and to still ultimately do what you wanted it to do.”

In casting around for biological answers to Psa, Plant & Food Research plant pathologists sifted through numerous fungi and bacteria from its extensive library of beneficial microorganisms.

“Ultimately our team at Ruakura found an Otago apricot fungi. that occurred naturally on the plant and did not cause any harm, was the best candidate for dealing with Psa.”

The yeast like fungi was found to populate the leaf surface of kiwifruit and effectively out-compete the Psa bacteria, disrupting the Psa cells on the leaf and affecting its ability to colonise the plant’s stomata. 

Partnering up with commercial partners Zespri and UPL provided the horsepower to translate the discovery into a commercial format, including manufacturing in a major bio-fermentation processing plant for the production of the beneficial microorganism.

Now produced in a commercial form and sold as AureoGold, the spray has proven to also act as an elicitor that activates a kiwifruit plant’s host defence genes, allowing the plant to react quicker to Psa attack, and with greater vigour.

Now approaching its third year on the market and enjoying good commercial success, Pringle says researchers are engaged with trials around the world to determine what other diseases AureoGold may prove adept at controlling.

“Kiwifruit is obviously a vital crop here in NZ, but globally it forms a very small part of the horticulture sector, so there is a lot of excitement in the trials running right now in a number of countries across a wide range of fruit and vegetables to see what else it can control.”

The commercialisation of the treatment is not the first win for the Plant & Food Research team, whose portfolio of bio-controls include Botry-Zen for controlling botrytis in grapes and BlossomBless for fireblight control in apples. They are among the first treatments of their type developed for horticulture in NZ.

“And there is no shortage of candidates for other targeted treatments.”

Bio-control also includes the likes of pheromone treatments such as those developed to successfully control codling moths in apple crops. 

Cutting edge work is also taking place in the emerging field of biotremology, which uses the mechanical production of insect vibrational signals to disrupt their mating behaviour.

Pringle is currently in the process of completing a Kellogg leadership programme on bio-control’s potential.

“There are a few roadblocks here in NZ to a sector that has a lot of potential. We are not short of talent and AureoGold highlights the value of being able to bring commercial and research parties together to commercialise the science.”

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