Kiwifruit disease Psa-V ’stuns’ NZ region

Vine disease Psa-V has been discovered close to the extremes of New Zealand’s Waikato region, but the country’s Kiwifruit Vine Health (KVH) believes it can be contained if growers pull together with a proactive approach.

 

KVH president Barry O’Neil told www.freshfruitportal.com laboratory confirmation was received last night that a gold kiwifruit (Hort16A) orchard in the Te Awamutu area was positive to the disease, while samples from a neighboring orchard showed preliminary positive results.

 

“We’ve established a 12km (17.45mi) controlled area around these orchards, and the 26 growers within this controlled area have all been contacted,” he said.

 

“We’re working with the postharvest operators that are supporting these growers to advise them on the best approaches that they can take to minimize the risks of Psa, such as restricting the movement of plant material and risk items, and the need to constantly monitor the orchards to ensure that if Psa does occur that they find it early.

 

“There’s a need for good hygiene practices as far as what comes onto the orchard and working within the orchard, and there’s a need for crop protection to minimize the risks that Psa can arise through the wind.”

 

He added the identification reinforced the importance for both a rigorous and collective approach to the disease with a national pest management strategy, which growers were being asked to vote for.

 

KVH Waikato co-ordinator Richard Glenn told www.freshfruitportal.com growers in the area were ’stunned’ by the detection.

 

“To think where it’s been located, which is north of Te Awamutu, it’s gone across the whole of the Waikato, almost to the furthest extreme of where orchards are located and dropped in on one, so that’s taken us by surprise,” he said.

 

“We would have thought it would have probably started at Matamata hills and worked its way back this way, but this is very disappointing.

 

“In my opinion it suggests it wasn’t airborne to get to that point in the middle of nowhere, but the KVH head office will do what they call a trace-back and that may take a few weeks; they do some very in-depth research to see where it may have come from and you go from there.”

 

He said regardless of how the trace-back turned out, growers had to be practical and learn from the experience of others.

 

“It might not be the fault of the grower, it might just be absolutely bad luck, so what they’ve got to do – as I said in an email to growers in the Waikato – is move forward and adopt the strategies and listen to the people in the Bay [of Plenty] who have been living with this disease for the last two years.

 

“I talked to people a lot and they asked me about the Pukekohe outbreak – again, another isolated outbreak, had to go across a lot of orchards, but however that trace-back is, don’t dwell on it.

 

“The reality is at the moment, they’ve pulled out some of the Hort16A up in Auckland and they haven’t had any more positives since that one quite a while ago now, and they must be doing proactive things to contain it.”

 

He said around 75% of Waikato’s 380ha of kiwifruit was dedicated to the Hayward crop, while between 20-25% was Gold – mostly with the Hort16A variety.

 

While the Hayward variety is less susceptible to the disease than Hort16A, and Waikato growers have the advantage of large distances of 2-10km (1.24-6.2mi) between orchards.

 

If growers are complacent it could have devastating consequences for the area.

 

“The problem is that the problem is here, it’s arrived, and therefore as a grower group we’ve got to be fairly united in a strategy going forward, and if we’re not united this disease will just roll through the Waikato quietly.

 

“If you think ‘it’s not going to hit me, Hayward’s fine’ that’s the wrong approach, because Hayward will slowly succumb to it.

 

“I was up on the first grower visit last year to Italy and saw Italian kiwifruit after four years. You do have to manage it, like any horticultural crop you’ve got to manage it, but this one’s a vicious little beast, and you just have to adopt best practice.”

 

He added around 60% of the region’s kiwifruit was organic, but they could still use organic certified crop formulations to protect the fruit.