Zespri and the Ministry of Agriculture and Forestry are urging Te Puke orchardists not to ‘shut up shop' as the scale of the kiwifruit disease situation appears to have grown.

There are now two orchards quarantined with the disease Psa and about a dozen more under close examination.

About 500 kiwifruit growers filled the auditorium at Te Puke's Orchard Church to hear from senior Zespri management on Tuesday afternoon.

The precise strain of the Psa disease is unknown at this stage, although MAF anticipates it will know from testing on Wednesday.

This information is key for the about 500 Bay of Plenty kiwifruit growers who received the ‘don't shut up shop' message when they attended a meeting with Zespri on Tuesday afternoon.

At the meeting Zespri technical division general manager David Tanner told the audience they do not know the severity of the Psa strand.

'Shutting up shop is not something we advocate. If the industry stops then we are being defeated. We have to be vigilant. Try to continue but mitigate the risks.

'How we act in the next weeks and months will determine its spread. We must move forward to mitigate the situation, not make it worse.”

Zespri CEO Lain Jager told growers the extent of the disease situation is unknown.

'We do not know the answer to that critical question today. It may be another week before we know.”

David told growers they need to regularly monitor their crops.

'This is a bacterial disease that may show up next week. One walk through is not going to show if you are free of Psa.”

Lain says it appears the confirmed infection has not created market access problems.

'It can't be transported on the fruit. There should be no market access implications but that's not to say there will not be.”

MAF and Zespri are still unsure how Psa got into the Te Puke orchard.

The two organisations are exploring four scenarios – human movement, plant movement, pollen transfer or the possibility the bacteria has existed in New Zealand for some time.

Zespri has postponed on-orchard field days and has told growers not to transfer plant material between kiwifruit sites.

Growers are also urged to thoroughly clean their equipment and sterilise pruning gear.