Kiwifruit growers say they are worried by how quickly the vine killing disease, PSA, has spread to orchards outside the initial contamination zone in the greater Te Puke region.
The virulent strain of the disease has been found on another 19 properties in the past week, two of which are in the previously unaffected Tauranga region.
New Zealand Kiwifruit Growers president Peter Ombler says the infection has spread much faster than expected.
He says a lot of work is going on to try to slow down the disease's spread, using protective sprays and stopping the movement of potentially infected equipment between orchards.
The organisation responsible for controlling the disease, Kiwifruit Vine Health, says it is vital growers maintain orchard hygiene and monitoring protocols.
However a spokesperson for the Independent Kiwifruit Growers' Association, Ross Hart, says the outlook is dismal, and trying to control the disease now is a pointless exercise.
Mr Hart says he is not convinced that any of the preventive measures, including protective sprays, are making much of a difference.
The head of New Zealand's largest kiwifruit orcharding company says a continual increase in the number of blocks confirmed as having PSA is a major concern.
Michael Franks of Te Puke based Seeka says the firm is working with competitor East Pack to find a control for PSA. It expects to have results by the end of the week from field trials of four chemical compounds.
Since it was first discovered near Te Puke in November last year, the disease has been found on 266 orchards, of which 151 have the virulent or V strain of PSA.
Kiwifruit Vine Health has extended its high risk zone in Bay of Plenty for the second time in six weeks.
It has also created a new Tauranga priority zone, which includes Papamoa, Matapihi and part of Welcome Bay, after tests confirmed the virulent strain on previously clean orchards.
