Nearly 50 new cases of Psa-V have been discovered over the past fortnight and officials are trying to work out how it is spreading over large distances.
This week there were 30 cases - eight in Te Puke, eight in Tauranga East, five in Tauranga West, four in Katikati, two in the Whakatane region, two in the Opotiki region and one in the Franklin region.
Last week, 18 new cases of Psa-V were identified - two in the Waihi region, three in the Katikati region, three in Tauranga East, three in Te Puke, three in the Whakatane region and four at Opotiki.
These cases bring the total number of infected orchards to 1305.
Kiwifruit Vine Health (KVH), the organisation established to lead the fight against Psa for the kiwifruit industry, said the spread was worrying but expected.
The organisation's main concern now was discovering how the disease spreads across large distances. KVH board spokesman Peter Ombler said: "Psa has now infected orchards in the Waikato and that's a significant distance to travel, so that's a major concern for us.
"We were expecting this to spread significantly through the Bay of Plenty and if you keep testing for it you'll continue to find it and that's the nature of the beast because it's an airborne spore, it can spread through an area very easily.
"The big problem is the movement of plant material because the last scenario we want is for infected plant material from the Bay of Plenty to end up in Northland. Whether it can move that far on its own, we don't know."
Mr Ombler said the best way to stop the movement of Psa-V throughout the Bay was to observe the best practices in terms of preventative spray, not move plant material and keep machinery and cutting equipment clean.
"By using preventative spray we're dampening the inoculant load in the orchards. Imagine it like a bushfire. You can't see the spark but you can see where the fire is, so you dampen the whole area and eventually you will get the spark and put it out. That's what the preventative spray does," Mr Ombler said.