The southern North Island has only 95ha of commercial kiwifruit, of which nearly 80ha are in or near Wanganui.
The Cooper family grow the most kiwifruit in the district - a total 47ha of vines - and the affected Pauls Rd orchard is next door to 16ha of Cooper kiwifruit.
"It could have been in the neighbour's vines last season. It could well be in our orchard ... we hope not," boss Noel Cooper said. He has been expecting the bacteria, and said it was a matter of when, not if. It has already infected 2262 New Zealand orchards - 75 per cent of the country's kiwifruit plantations.
Mr Cooper said the disease might cause small growers to pull out their vines, but his family was committed to continuing with kiwifruit.
"I don't think it's a death sentence - it's just something we have to get on top of. There's a lot of people that are surviving and it just means we have extra costs to control or keep Psa out."
He had to be philosophical.
"There's no point in crying if you are in business - there's lots of people worse off."
He said the Pauls Rd orchard had had a new owner recently, and its fruit was packed at Apata, a hot spot for the disease.
Staff members from the Apata packhouse regularly visit the orchards whose fruit they pack. Precautions are taken, but the bacteria may have reached Wanganui from Apata, via an infected bin, Mr Cooper said.
Over in Brunswick, Bruce and Diane Rhodes have about 5ha of kiwifruit that is also packed at Apata. Mrs Rhodes said they wouldn't be tearing out their vines and they had been taking preventive measures - banning vehicles from their orchard for the past year, and using preventive copper sprays.
Wanganui growers have some advantages as they fight off Psa - they don't grow the gold kiwifruit variety most susceptible to it, and most vines are on a Psa resistant Bruno rootstock. Psa arrived in New Zealand in the Bay of Plenty in 2010, and a report estimates it will cost the country between $310 million and $410 million from 2012-17.
In the three years since it arrived growers have learned a lot about how to live with it.
"The industry has developed some really good protocols. We can just jump on that bandwagon," Mr Cooper said.
The Psa bacteria affects only kiwifruit. If it grows on the outside of the plant it has no effect but when it gets inside, often through pruning cuts, it causes leaf spotting, wilting, oozing from the canes and sometimes death. The bacteria is spread by wind and weather. It can also move on people's shoes.
