An "important new tool" to control kiwifruit bacterial vine disease Psa has been launched in New Zealand.

AureoGold, which has been developed by Plant & Food Research in collaboration with Arysta LifeScience, is a natural yeast strain that is said to be able to reduce growth and spread of Psa bacteria.

It can be used during flowering and post fruit set, a time in the calendar when use of other controls for Psa is limited. AureoGold is a yeast found naturally on many different species of plants and fruits in New Zealand and is safe for bees.

AureoGold has been approved for use by the Ministry for Primary Industries under ACVM (agricultural compounds and veterinary medicine) regulations, and has BioGro Organic Certification. 

“New bio-bactericides allow growers options to manage disease on orchards,” says Dr Suvi Viljanen, general manager, science bioprotection at Plant & Food Research.

“AureoGold™ will provide kiwifruit growers, including organic growers, with an important new tool in their armoury to ensure plant health and good fruit yields despite the presence of the potentially devastating bacterial disease, Psa.

"This is a real achievement for our team, and yet another example of how we can work with industry to build new solutions to address key problems.”

Psa was discovered in New Zealand in November 2010, and is now present in around 92% of the regions where kiwifruit is grown in the country. Symptoms include 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 New Zealand yeast that forms the basis of AureoGold was identified in 2012, and was fast-tracked through glasshouse and field testing through a partnership with Zespri/KVH and Arysta LifeScience.