A total of 174 cases of myrtle rust have been found in the Bay of Plenty, 18 more than in December last year, and most of the infection sites are in Te Puke and Bethlehem.
The Bay of Plenty is the third highest region for myrtle rust detections in the country, with 283 confirmed cases in Taranaki and 179 in the Auckland area.
Of the 174 confirmed cases in the Bay, there are 44 affected sites in Te Puke, 30 in Bethlehem, 22 in Tauranga city (five more sites than in December) and 12 each in Welcome Bay and Ōmokoroa.
There is also 13 affected sites or properties in Rotorua, including the Kaimai Mamaku Forest Park, three more identified sites than in December last year.
A Biosecurity New Zealand spokesperson said the majority of these sites were on privately owned land and five on commercial properties, which included an orchard and two public conservation land properties.
The majority of the detections were on the plant Ramarama, but also native pohutukawa and the exotic myrtles Lilly Pilly/monkey apple, bottle brush and willow myrtle.
"Myrtle rust is likely to be more active during warmer weather with late summer and autumn likely to be the worst time for infection and spore risk, " the spokesperson said.
Myrtle rust has spread to 895 identified properties nationwide since 2017.
Biosecurity New Zealand has commissioned a $3.7m comprehensive research programme made up of more than 20 specific projects to better understand myrtle rust.
The Government is set to pump another $13.75 million into research to combat the spread of myrtle rust and kauri dieback in the next three years.
This is on top of previous research funding of $6.9m for myrtle rush.
Tauranga Moana Biosecurity Capital collective co-chairperson Graeme Marshall said the latest detection cases in the Bay was "very disappointing".
Marshall said a considerable amount of work was already going on to try and manage the risks, particularly in relation to pohutukawa on Mauao.
But continuing surveillance is the key to helping to manage the threat, he said,
"This is why were want 4.7 million New Zealanders to be part of the country's biosecurity team by reporting cases and helping to reduce the spread of this nasty fungal disease."
Marshall said whether it was myrtle rust, kauri dieback or some other invasive pest it needed everyone to play a role in combating any biosecurity threats.
Shane Grayline, the Bay of Plenty Regional Council's biosecurity team leader, said it was hard to imagine the region without our beautiful pohutukawa trees lining our coasts.
"Or rata vines cloaking trees in the bush or being able to enjoy feijoas or even worse, and what would happen to our beekeeping industry if we lose our mānuka.
"However these are the species that myrtle rust threatens and why we are working hard with MPI and landowners to stop the spread of the disease," he said.
If a plant is showing symptoms people should not touch the plant or collect samples.
Anyone who accidentally come in contact with an affected plant or the rust, should bag their clothing and wash their clothes, bags, shoes and boots.
If you can, take a photo of the rust and the plant it's on and phone the MPI's exotic pest and disease hotline 0800 80 99 66.