Our Changing World

In 2010 the Psa-V bacterial disease was found in a Bay of Plenty kiwifruit orchard. This was the beginning of a terrible ordeal for many kiwifruit growers. It devastated crops, resulting in the loss of hundreds of jobs, and hundreds of millions of dollars. But though it spread to some other areas in the North Island, it never made it across the Cook Strait. Claire Concannon learns about the science behind keeping this microbe out of Te Waipounamu.
Sign up to the Our Changing World monthly newsletter for episode backstories, science analysis and more.
Learn more:
The Plant and Food Research (today the Bioeconomy Science Institute) team who worked on science to help with the kiwifruit Psa crisis won the Prime Minister’s Science Prize in 2017.
In 2012 Alison Ballance reported on the hunt for resistance genes so kiwifruit plants could be more resilient in the face of this bacteria.
As In-Depth reporter Farah Hancock detailed earlier this year, 95% of the kiwifruit grown here are actually exported - an earner of $4.5 billion in 2025.
Guests:
Falk Kalamorz
Rebecca Manners, Bioeconomy Science Institute
Dr Ed Morgan, Bioeconomy Science Institute
Leanne Stewart, Kiwifruit Vine Health
Go to this episode on rnz.co.nz for more details

Ketamine was first developed as an anaesthetic, and today is taken by some as a party drug. But since 2000, research has emerged showing it is also helpful as a medication for some people with treatment-resistant depression. While initial studies used ketamine injections, recent research has shown the advantages of taking it in oral form. Now clinical trials are underway to determine if a New Zealand-developed ketamine pill is safe and effective enough to get the regulatory tick.

Sign up to the Our Changing World monthly newsletter for episode backstories, science analysis and more.…
Go to this episode on rnz.co.nz for more details

In the Auckland suburb of Mt Albert there's a particular brand of doomsday prepping going on. Our Changing World visits the Bioeconomy Science Institute to meet some scientists figuring out how to build an army of Samurai Wasps just in case Aotearoa is invaded by Brown Marmorated Stink Bugs.
Sign up to the Our Changing World monthly newsletter for episode backstories, science analysis and more.
Learn more:
MPI's website has more detail on the Brown Marmorated Stink Bug and what to do if you find one.
From December 2025 a new biosecurity inflight video about being vigilant is being played to incoming visitors.
Our Changing World did a deep dive into the impact BMSB would have on New Zealand, back in 2019. 
Guests:
Dr Gonzalo Avila, Senior Scientist - Biological Control, New Zealand Institute for Bioeconomy Science Limited
Karina Santos, Senior Research Associate, New Zealand Institute for Bioeconomy Science Limited
Dr Scott Sinclair, Manager, Operational Readiness - Plant & Environment, Biosecurity New Zealand
Go to this episode on rnz.co.nz for more details

Our Changing Word heads to Whangārei to speak to a Northland Regional Council scientist whose been using stormwater drains to estimate the scale of our plastic pollution problem. Plus, just outside Christchurch, one of New Zealand’s biggest lakes is home to the ‘canary in the coalmine’ of wetlands. The secretive and elusive Australasian bittern seems to be in trouble - how can we help?
Sign up to the Our Changing World monthly newsletter for episode backstories, science analysis and more.
Learn more:
Join Alison Ballance on a kayak across a lake to listen to some booming bittern crooners.
Listen to the nine to noon interview with John Sumich about the 2025 Matuku muster.
The research into microplastics was part of the AIM2 project, which was reported on in 2021 as part of the OCW episode ‘Unwelcome visitors’.
Another source of microplastics is textile waste, but an international project is looking to a future where our clothes are fully biodegradable.
Guests:
Richard Griffiths, Northland Regional Council
Peter Langlands, Bittern Conservation – New Zealand
Harry Caley, Department of Conservation
Go to this episode on rnz.co.nz for more details

In Dunedin the local tree crop association has been looking after a heritage apple orchard, but some mixed up labels meant they weren’t quite sure what varieties they had. A chance encounter at a public open day sets one young researcher on a scientific quest to ID them all. Plus, in a nursery in Rotorua, a propagation scientist is figuring out the best way to grow a native tree from cuttings.
Go to this episode on rnz.co.nz for more details