Myrtle Rust (Uredo rangelii)
The rust caused by Uredo rangelii, which is known as Myrtle rust, was detected in Australia on 23 April 2010 on a cut flower growing property on the central coast of New South Wales. The rust was confirmed on Agonis flexuosa (willow myrtle), Syncarpia glomulifera (turpentine) and Callistemon (bottlebrush) species growing on and near the property.
The Agonis plants used for cut foliage were very heavily infected whilst low levels of infection were noted on wind-break turpentine trees some metres away and a few Callistemon shrubs along the driveway leading onto the property. Currently Myrtle rust is understood to be a part of the guava rust complex that infects the Myrtaceae family of plants. The Myrtaceae encompasses many Australian native species. Myrtle rust produces lesions on young, actively growing leaves and shoots, as well as on fruits and sepals on some species. 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.
Rusts are highly transportable. Their spores can be spread on contaminated clothing, infected plant material and equipment and by insect movement and wind dispersal. Fungi in the guava rust complex affect commercial plant growing operations and native ecosystems. They typically attack young plants and new growth on established plants.
Research information from overseas indicates that plants vary significantly in their susceptibility to guava rust. Individual variations in susceptibility to Myrtle rust have also been observed in the host testing work undertaken at CSIRO Black Mountain. Selection of plants that are resistant or highly tolerant of infection is relatively straightforward for many ornamental and production species.
Myrtle rust is considered widespread on the eastern seaboard of NSW from the Shoalhaven to the Queensland border. Recent detections on the North Coast from Ballina to Queensland have been reported from bushland, nurseries, gardens and bush food production sites. Myrtle rust is present in Queensland and eradication measures are ongoing.
Sample photographs of myrtle rust are produced for identification:-
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Acmena smithii (lilly pilly)
Agonis flexuosa (willow myrtle) 'Afterdark' (images), 'Burgundy' (images), 'Jeddas Dream' - disease severity may be severe
Angophora floribunda (rough-barked apple)
Austromyrtus dulcis (midgen berry)
Austromyrtus inophloia (see Gossia inophloia) - may be severe
Backhousia citriodora (lemon-scented myrtle) - may be severe
Backhousia myrtifolia (grey myrtle)
Callistemon viminalis (weeping bottlebrush)
Callistemon salignus (willow bottlebrush) (images)
Callistemon 'St Mary MacKillop'
Chamelaucium uncinatum (Geraldton wax)
Choricarpia leptopetala (brown myrtle or rusty turpentine)
Decaspermum humile (silky myrtle)
Eucalyptus agglomerata (blue-leaved stringybark) (images)
Eucalyptus deanei (mountain blue gum or Deane's gum)
Eucalyptus elata (river peppermint gum)
Eucalyptus pilularis (blackbutt)
Eugenia reinwardtiana (beach cherry)
Gossia acmenoides (scrub ironwood)
Gossia bidwillii (scrub python tree)
Gossia floribunda
Gossia fragrantissima (sweet myrtle) - THREATENED
Gossia hillii (scaly myrtle)
Gossia gonoclada (angle-stemmed myrtle)
Gossia inophloia 'Aurora' and 'Blushing Beauty' (syn. Austromyrtus inophloia) (images) - may be severe
Lenwebbia prominens (southern velvet myrtle)
Leptospermum petersonii (lemon-scented tea tree)
Leptospermum rotundifolium (round-leaved tea tree)
Lophomyrtus bullata 'Rainbow's End'
Lophomyrtus x ralphii 'Red Dragon', 'Black Stallion', 'Krinkly'
Melaleuca alternifolia (tea tree)
Melaleuca cajuputi (swamp tea tree)
Melaleuca fluviatilis
Melaleuca leucadendron
Melaleuca quinquenervia (broad-leaved paperbark) (images) - may be severe
Melaleuca linariifolia 'Claret tops'
Melaleuca nodosa (prickly-leaved paperbark) (image)
Metrosideros collina 'Tahiti' and 'Fiji' (images)
Metrosideros thomasii (New Zealand Christmas bush) (images)
Myrtus communis (common myrtle) - may be severe
Pilidiostigma glabrum (plum myrtle)
Rhodamnia argentea (silver myrtle)
Rhodamnia costata (malletwood)
Rhodamnia dumicola
Rhodamnia maideniana (smooth scrub turpentine) (image)
Rhodamnia rubescens (scrub turpentine) (images) - may be severe
Rhodamnia sessiliflora (iron malletwood)
Rhodamnia whiteana (white malletwood) (image)
Rhodomyrtus psidioides (native guava) - may be severe
Syncarpia glomulifera (turpentine) (images)
Syzygium angophoroides (watergum)
Syzygium anisatum (aniseed myrtle) - may be severe
Syzygium australe 'Meridian Midget'
Syzygium canicortex (yellow satinash)
Syzygium jambos (rose apple) - may be severe
Syzygium luehmannii (small-leaved lilly pilly, riberry)
Syzygium luehmannii x Syzygium wilsonii 'Cascade' (lilly pilly) (images)
Syzygium oleosum (blue lilly pilly)
Syzygium paniculatum (brush cherry) - THREATENED
Syzygium tierneyanum (river cherry)
Tristania neriifolia (water gum) (images) - may be severe
Uromyrtus australis (peach myrtle) (image) - THREATENED
Uromyrtus lamingtonensis (lamington peach myrtle)
Waterhousea floribunda (weeping lilly pilly)
Waterhousea heterophylla
Xanthostemon chrysanthus (golden penda)
Xanthostemon oppositifolia
Xanthostemon youngii
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