Only three of New Zealand's kiwifruit growing regions remain free of the vine disease Psa-V following it being found for the first time in Wanganui.

Orchards in the South Island, Whangarei and North-west Auckland are currently believed to be disease free, but it is present in 2265 orchards across all other regions – most intensively in Te Puke where 1083 or 99 per cent of orchards are infected.

Pseudomonas syringae pv actinidiae was positively identified on Hayward male vines on an orchard near Wanganui last Friday. Since then, two other nearby orchards have also been confirmed Psa positive. All orchards are showing secondary disease symptoms including red exudate and cane dieback, according to Kiwifruit Vine Health.

A ‘Wanganui Controlled Area' has been established with a 10km radius from the first infected orchard. All three Psa positive orchards are included in this controlled area along with four others – seven orchards in total.

KVH and postharvest representatives met with local Wanganui growers yesterday to give them an update on the situation and provide support and best practice advice for managing orchards in a Psa environment. Growers are also being provided with monitoring information and KVH resources, including Psa symptom guides to help them identify signs of the vine disease.

The Wanganui/Horowhenua region extends from New Plymouth up to Taumaranui, reaching as far east as Taihape and as far south as the Kapiti Coast. There are 25 orchards in this region, totalling 92 hectares of kiwifruit. Fourteen of these orchards are located within 20km of Wanganui.

KVH CEO Barry O'Neil says the Psa incursion into Wanganui/Horowhenua reinforces that no growing region is protected from the vine disease – and spring is also a time when symptoms will show after winter dormancy.

'All growers, in all regions, must do all they can to protect their orchards before it reaches their orchard or region. Continuing to monitor orchards and carry out best practice orchard hygiene is essential to reduce the risk of Psa-V entering and/or establishing in orchards,” advises Barry.

Storms create ideal conditions for the spread of Psa and spring is a time when symptoms will start showing after winter dormancy. Recent storms have seen the use of the antibiotic spray KeyStrepto significantly increase, with KVH has receiving more than 100 requests for audits to permit spraying this week.

Growers must not apply KeyStrepto until they've received a KVH audit, giving clearance to spray. They must also notify neighbours at least 12 hours (preferably 48 hours) before spraying. Growers are recommended to ensure a good copper cover is in place prior to high-risk weather periods.