Yesterday Mr O'Neil held a meeting for about 20 local growers at Wanganui's Collegiate Motor Inn, to update them on the findings.
He said there was hard work ahead for them, and it would be a stressful time. They were disappointed, but philosophical.
The important thing now was to minimise the spread and impact of the bacterial disease. Using copper sprays can help prevent it.
The growers were taught how to monitor vines and asked to take samples of any, especially male vines, that looked infected. Samples from the lower North Island will now be tested free of charge.
Vines that test positive for the Psa bacteria must be cut out and either burned at high temperatures or buried.
"We're recommending growers to dig a reasonably sized burial pit. Burning at low temperatures could spread the disease through eddies of the fire."
Plant material and orchard equipment cannot be moved out of a newly created control zone around the affected orchards.
Wanganui growers have a few things in their favour - most of the kiwifruit there is green Hayward varieties grafted on to reasonably Psa-resistant Bruno rootstocks. There is none of the early gold variety that has no resistance.
The growers also have three year's accumulated experience of dealing with the disease to learn from. It first arrived in the Bay of Plenty in 2010.
Against them is Wanganui's climate - wetter and colder than the Bay of Plenty, which could reduce vines' resistance.
There was no point speculating about how the bacteria got to Wanganui, Mr O'Neil said.
"In other regions where we've done detailed investigations we've never been able to identify what was involved. We don't believe it was a wind-borne spread. It must be plant or contaminated machinery. There's a number of possibilities."