Plant Pest Threat - Uredo rangelii (Myrtle rust)
Look out for Uredo rangelii (Myrtle rust)
Newly formed bright yellow pustules of Myrtle Rust on Agonis flexuosa c.v. Afterdark
Myrtle Rust
Myrtle Rust an introduced disease caused by the fungus Uredo rangelii. Myrtle Rust, which is part of the eucalyptus/guava rust complex, has been confirmed in New South Wales, Queensland and Victoria on a wide range of host plants in the family Myrtaceae.
The disease is of serious concern to Australia due to the possible significant impact on native forests, parks and gardens, nurseries and Eucalypt plantations. The Myrtaceae family is a dominant plant group in natural ecosystems. The susceptibility of plants within the Myrtaceae family to myrtle rust ranges from high susceptibility to tolerant. Bioclimatic data indicates that northern and eastern Australia are most at risk as high rainfall and temperatures are favourable for the development of the disease. The South Australian climatic environment is less suited to myrtle rust and the potential economic and biological impact of the disease on South Australian industries and natural ecosystems is likely to be low.
It is expected that the higher rainfall coastal areas of South Australia are most at risk, namely the South East, Kangaroo Island, Fleurieu Peninsula, lower Yorke Peninsula and lower Eyre Peninsula. Even in areas of drier climate that are generally unsuitable for the pathogen, nurseries, glasshouses and some home gardens have the potential to provide microclimates that are conducive to infection and spore development, given an adequate supply of susceptible young foliage.
Identification
Myrtle Rust produces lesions on young, actively growing leaves and shoots, as well as on fruits and sepals. Leaves may become buckled or twisted as a result of infection.
On turpentine and callistemon rust lesions are purple in colour, with masses of bright yellow or orange-yellow spores. Occasionally, they may have dark brown spores. Severe rust disease in young trees may kill shoot tips, causing loss of leaders and a bushy habit.
Host Species
In Australia, Myrtle Rust has recently been detected on Agonis (willow myrtle), Syncarpia (turpentine) and Callistemon (bottlebrush) species. Internationally, there are unconfirmed reports of infection on some Eucalyptus species. It has also been confirmed on Myrtus, Syzygium and Heteropyxis species overseas
Newly formed bright yellow pustules of Myrtle Rust on Agonis flexuosa c.v. Afterdark
Spread
Rusts are highly transportable. The most common dispersal mechanism is via wind but they may also attract bees who work the spores on leaves. The spores can also be spread via contaminated clothing, infected plant material and insect movement.
NEVER MOVE SUSPECTED CONTAMINATED OR INFECTED MATERIAL, CALL BIOSECURITY S.A.
Newly formed bright yellow pustules of Myrtle Rust on Turpentine
If you see anything unusual, call the Exotic Plant Pest Hotline 1800 084 881
Supported By
Queensland
Biosecurity Queensland
New South Wales
Industry & Investment NSW
Australian Capital Territory
Environment ACT
Victoria
Department of Primary Industries
Tasmania
Department of Primary Industries, Parks, Water and Environment
South Australia
Primary Industries and Regions Biosecurity SA
Western Australia
Department of Agriculture
Northern Territory
Department of Primary Industry, Fisheries and Mines
Commonwealth
Department of Agriculture,Fisheries and Forestry
Disclaimer
The material in this publication was prepared from the most up-to-date information available at the time of publication. It is intended as a guide only and the publisher accepts no responsibility for errors.
Photographs
A. Carnegie
Prepared by
Biosecurity SA Revised Feb. 2012