OPTION 1: Disease Index for the Rust Puccinia psidii
sensu lato on Rhodamnia species in Australia

The rating system shown here is being developed for potential use in a QLD/NSW CRC project using Rhodamnia in a sentinel site approach.

One of the more susceptible genera or Myrtaceae to be affected by P. psidii is Rhodamnia, including R. rubescens, R. sessiliflora, R. angustifolia, R. madeniana and R. argentea.

Scrub Stringybark, Brush Turpentine, Brown Malletwood

Rhodamnia rubescens Scrub Stringybark, Brush Turpentine, Brown Malletwood

Rainforest tree of eastern Australia - grows in a variety of different rainforests from the Batemans Bay region of southeastern New South Wales to Gympie in southeastern Queensland. The fruit is eaten by various birds, including the Brown Cuckoo Dive, Fig Bird, Green Catbird and Rainbow Lorikeet. Rust susceptibility high - infection results in severe shoot and foliage dieback.
Lamington NP, Queensland. Photo G. Pegg DEEDI Natural distribution of Rhodamnia rubescens
Rhodamnia rubescens, Lamington NP, Queensland. Photo G. Pegg DEEDI

Rhodamnia maideniana Smooth Scrub Turpentine

Smooth Scrub Turpentine Rare sub-tropical rainforest plant of eastern Australia. It is listed on ROTAP (Rare or Threatened Australian Plants) with a rarity factor of 2RC. Occurs in coastal areas, north of the Richmond River, New South Wales and adjacent areas over the border into Queensland. Rust susceptibility � high - infection results in severe shoot and foliage dieback. Flowers have also been recorded as being infected.

Rhodamnia maideniana Springbrook NP Queensland Photo G. Pegg, DEEDI

Rhodamnia argentea Malletwood, White Myrtle, Silver Leaf, Silver Malletwood and White Turpentine


Healthy Silver Myrtle Rainforest tree of eastern Australia � Hastings River in New South Wales to Bowen, Queensland. The fruit is eaten by various birds, including the Green Catbird, Lewin's Honeyeater and Regent Bowerbird. Rust susceptibility - Moderate

Rhodamnia angustifolia narrow leafed malletwood

Listed under the Nature Conservation Act as endangered. Rust susceptibility � high infection results in severe shoot and foliage dieback narrow leafed malletwood
Rhodamnia angustifolia Brisbane, Queensland. Photo G. Pegg DEEDI

DISEASE SYMPTOMS

Rhodamnia species appear to be highly susceptible to Puccinia psidii with infection occurring on leaves, shoots, stems, flowers and fruit. Disease is initiated on young foliage with severe infection resulting in shoot and stem dieback and foliage growth. It is likely the repeated infection will result in reduced growth rates. Infection of flowering structures and fruit has been recorded on R. rubescens and R. sessiliflora. Infected fruit senesces prematurely but the impact on seed viability is not yet known.

Category 1

Rhodamnia Category 1
  • Young leaves
  • Very low levels of disease with only a few spots per tree or bush
  • Pustules with yellow spores present on some leaves

Category 2

Rhodamnia Category 2 Young shoots and expanding leaves
  • Moderate number of new leaves/shoots showing symptoms of infection
  • Infected leaves with more than 10 individual spots
  • Pustules with yellow spores present on all leaves
Older leaves
  • Few lesions present
  • Pustules with spores absent

Category 3

Rhodamnia Category 3
Young shoots and expanding leaves
  • The majority of leaves showing some evidence of infection
  • Pustules with yellow spores present on all infected leaves
  • Evidence of infection on juvenile stems with the presence of pustules and spores
Older leaves
  • Lesions present on 15-20% of older leaves with some evidence of blighting or coalescing of leaf spots
  • Pustules with spores or evidence of old pustules on some leaves

Category 4

Rhodamnia Category 4
Young shoots and expanding leaves
  • Infection present on all new growth including shoots, juvenile stems and expanding foliage
  • Pustules with yellow spores present on all infected leaves, shoots and stems
Older leaves
  • 20-50% of older leaves with evidence of infection
  • Severe blighting and dieback of some foliage and stems
  • Pustules with spores present on most foliage showing symptoms of infection

Category 5

Rhodamnia Category 5
  • Dieback/death of most new shoots and stems and associated premature senescence of infected foliage