Myrtle Rust and Eucalyptus Pests

2017 FGR Annual Conference
Report No:
Report Date:
October 18, 2017
Lindsay Bulman: Scion

Myrtle rust

Conference presenter: Lindsay Bulman, Scion

Presentation:  Myrtle Rust and Eucalyptus Pests

Myrtle rust, caused by the fungus Austropuccinia psidii, reached New Zealand for the first time in April 2017, wind-borne from Australia to Raoul Island. From here it has moved to Northland, Taranaki, the Waikato and the Bay of Plenty. It is easily spread: spores can be transported on cars, clothing, birds and animals, and tree nursery stock. By mid October 2017 it had been found at some 121 confirmed sites, with the number rising steadily.

The rust affect foliage, fruits and flowers of a wide and expanding host range.

Knowledge/findings to date

  • New Zealand has around 30 native myrtaceous species, including kanuka, manuka, pohutakawa, rata, ramarama and swamp maire.
  • To date (Nov 2017) the most susceptible NZ species appear to be Lophomyrtus bullata – ramarama (57 infected plants found) Metrosideros excelsa, M. kermacadensis and other species – pōhutukawa, northern rātā, and southern rātā (35 infected plants found).

Myrtle rust on (i) pohutakawa and (ii) ramarama

  • Many exotic myrtaceous species also grow in New Zealand, including a number of eucalyptus species.
  • International experience suggests control options are limited: at present efforts are being focussed on:
    • detecting and destroying infected material, and
    • preventing further spread by imposing movement restrictions on nursery stock from certain regions.
  • In time more control options, including chemical control and the identification of resistant hosts, may emerge.
07 Myrtle Rust (1.20 Mb)