That’s the latest from Darren Faire, sales and marketing lead at UPL, formerly Arysta LifeScience.
 

The new bio-bactericide was developed by Plant & Food Research in collaboration with UPL, and is a natural yeast strain that provides protectant activity against Psa bacteria.
 

Pseudomonas syringae pv actinidiae (Psa) was discovered in New Zealand in November 2010.
 

The bacteria is present in 92 per cent of the regions where kiwifruit is grown in this country, with symptoms including leaf spotting, shoot die-back, cane and leader die-back, bud browning, red-brown exudate from leaders and trunks and, in severe cases, plant death.
 

After the discovery of Psa, Plant & Food Research scientists began screening their library of microbes to identify any with the

potential as a bio-bactericide control agent.
 

The NZ yeast that forms the basis of Aureo Gold was identified in 2012 and comes from a Central Otago apricot.
 

Its development was fasttracked through glasshouse and field-testing through a partnership with Zespri/KVH and UPL.
 

“Aureo Gold’s mode of action is still not fully understood,” Darren Faire says, and studies by Plant & Food Research and AgResearch are ongoing to better understand the complex nature in which Aureo Gold brings about a reduction in Psa.
 

Research to date suggests that it has multiple modes of action, including, but not limited to, the following:

• Physical disruption of Psa cells on leaf surfaces, which appears to affect the ability of Psa to colonise stomata – a key point of entry into the leaves.

• Acting as an elicitor activating kiwifruit host defence genes. Studies have shown Aureo Gold to prime at least two kiwifruit

host defence genes, allowing the plant to react more quickly and to a higher degree to the presence of Psa.
 

The new product has gone through extensive field trialling on both Hayward and Gold3 (more than 30 trials) across kiwifruit

growing regions of South Auckland, Bay of Plenty and Gisborne.
 

Darren Faire says applied alone, it has proven to provide similar levels of protection as copper bactericide.
 

Trials have focussed on evaluating its performance not just alone but also in a programme with other bactericides.
 

Efficacy, rate range, timing, crop safety, fruit set, russet and storage have all been assessed.
 

A key benefit for users is the flexibility it provides when it comes to application timing.
 

“Aureo Gold can be used whenever there is a need to protect from Psa,” says Faire.
 

It can be applied anytime from budbreak to six weeks post flowering with no phytotoxic effects on foliage or developing fruit.
 

Field trialling has confirmed no adverse effects arising from multiple spray applications of Aureo Gold during the preflower or flowering and fruit set periods; and it is bee friendly.
 

It provides a new tool in Psa management and should be used in a programme with alternative products, Faire recommends.
 

“With BioGro certification it will be a welcome option for both organic and conventional producers alike.”
 

Along with application flexibility growers will also enjoy Aureo Gold’s ability to be tank mixed with a wide range of currently

used bactericides, fungicide, and insecticides.
 

Being a bio-bactericide, it needs to be managed to maximise its shelf life capacity.
 

If stored refrigerated between 1 and 5°C it is viable for up to 12 months.
 

Once the product has left refrigeration, it can then only be stored for up to four months in a cool dry place below 25°C.
 

Aureo Gold comes in a one kg pack.
 

For more detail contact your local UPL regional manager.