The Myrtle Rust threat - we need your help!
Every landowner with a patch of bush has a major role to play in keeping Tasmania free of the various pests and diseases that affect mainland Australia. A new threat that has recently arrived on the mainland is Myrtle Rust (Uredo rangelii), a member of a rust fungi complex that causes significant disease on plants in the Myrtaceae family. This is of great concern to Australia, as many of our keystone forest species are in the Myrtaceae family.
The distinctive yellow spores of Myrtle Rust on Terpentine tree (Syncarpia glomulifera). Photo by Dr Angus Carnegie, I&I NSW.
Myrtle Rust is spreading on the mainland and now extends from the NSW South coast right up to South East Queensland. Indeed, it has even been found in a few nurseries as far North as Cairns. Almost 100 species have now been affected. It is not certain how susceptible Tasmania is to incursion by this warm, moisture loving rust fungi. However, the Bass Strait islands, Northern and North Eastern lowlands and Hobart area are predicted to be sites with the more favourable climate for its establishment.
As has been so disastrously demonstrated in NSW and Queensland, Myrtle Rust spreads quickly and widely. That is why Tasmania has taken strong steps to keep this disease out. All imports of Myrtaceae plants into Tasmania have been banned since July 2010 and all imports of non-Myrtaceae nursery stock must be treated with a fungicide to prevent Myrtle Rust hitching a ride into Tasmania on non-host plants.
Our campaign to keep Myrtle Rust out also includes active surveillance for any signs of the disease in Tasmania. This is where you, as a landowner, have a major role to play.
With the warmer weather here, the tell-tale signs of Myrtle Rust (distinctive yellow spores on the leaves) are easy to see and cannot be mistaken as no other rusts are present on Tasmanian Myrtaceae species.
While the range of tree and shrub species that are susceptible to Myrtle Rust is large, the most common Myrtaceae in our bushland and gardens include gum trees (Eucalyptus ), tea trees (Leptospermum), paperbarks (Melaleuca) bottlebrushes (Callistemon) and white kunzea (Kunzea). Willow myrtle "after dark" (Agonis flexuosa) is a particularly susceptible garden species that is present in Tasmania.
Please note, however, that yellow rust fungi spores can be present on other families of plants in Tasmania - these are not Myrtle Rust (e.g. blackberry and grass rusts etc) and need not be reported.
Please keep a keen eye out for the signs and if you do see anything you think might be Myrtle Rust, don't collect a sample, as that may spread the disease. Instead:
- Check that the yellow spores are on a plant in the Myrtaceae family
- Take a photo
- Note where you saw it - a GPS location is ideal, but otherwise the best description of the site you can give
- Tie a ribbon or some other marker to the plant
- Report your sighting as soon as you can to the hotline 1800 084 881 (all hours).
The opportunity to contain and eradicate Myrtle Rust is no longer there for NSW and Queensland. If the disease were to turn up in Tasmania, we may be able to contain and eradicate it if, and only if, sightings are reported before the disease becomes well-established. So, please don't delay if you think you've seen what looks like Myrtle Rust.
For more information go to www.dpipwe.tas.gov.au/ and look up ‘Biosecurity.
Barry Calderbank and Tim Rudman, DPIPWE
(Original article from Private Land Conservation Program's newsletter 'The Running Postman', December 2011, p3)