By Tony Beauchamp, Technical Advisor
As you’re lying under your favourite pohutukawa tree this summer, look up. If you see any yellow spots on leaves, flower buds (or fruits of other Myrtaceae species), reach for your phone, take a photo and call the Ministry of Primary Industries (MPI) hotline—0800 80 99 66.
Don’t hesitate, and don’t touch it! If it is myrtle rust (Pucinnia psidii), a fungus that attacks Myrtaceae species (including rata, manuka, kanuka, ramarama, eucalyptus, guava and feijoa), it will be as mobile as talcum powder.
If you are off to Australia or Indonesia at Christmas, make extra certain your shoes, bag and equipment are clean before coming home.
Myrtle rust is not in New Zealand yet, but since October 2014, it has spread to Sumatra, Indonesia. It is also established and spreading on Australia’s east coast and in Tasmania, which makes it worryingly nearby.
Because its spores are like a fine powder this rust is considered highly likely to get to New Zealand. The spores can be transmitted by wind and insects – although we consider the main risk into New Zealand is transmission via peoples’ shoes and personal items.
Impacts of myrtle rust
The rust’s impact on native plants and ecosystems will depend on the variety that gets into New Zealand, but it will impact all of New Zealand’s Myrtaceae to some degree and a loss of some Myrtaceae in their natural state is inevitable.
New threatened species could certainly be created and ecological integrity will be compromised especially where myrtles are a dominant species. Ecosystem services, especially for commercial activities (e.g. manuka honey industry), tourism, recreation and landscape values will all be adversely affected to various extents.
What to do?
If or when it gets here, we’ll only have a tiny window of opportunity for eradication. Which is where you come into the picture. If you think you see something that looks like myrtle rust, call the MPI hotline straight away. Remember, don’t be tempted to touch it because if you do, you’ll spread it.
There’s a sobering lesson in the story of Australian inspectors who charged in and out of infected sites for samples, leaving clear radial lines of infection along their exit routes!
DOC is working with MPI to prepare for this incursion. Critical hygiene measures will be necessary to avoid the Australian mistake.