Fire and rust – the impact of Austropuccinia psidii (myrtle rust) on regeneration of Myrtaceae in coastal heath following wildfire

Abstract

In April 2010, the exotic rust fungus Austropuccinia psidii was detected for the first time in Australia, with the host range rapidly increasing to >350 species from 58 genera within the family Myrtaceae. Commonly known as myrtle rust, the disease is well established in native ecosystems, particularly in New South Wales (NSW) and Queensland, impacting on a range of species and associated environments. While fire is considered an important selection agent in the development of Australia’s native flora, re-sprouting and germination of seedlings en masse is ideal for the development and spread of A. psidii. Our study took advantage of a unique opportunity to assess the impacts of myrtle rust on species of Myrtaceae regenerating after a wildfire in a northern NSW coastal heath environment. Austropuccinia psidii infection was found on all species of regenerating Myrtaceae with impacts ranging from minor leaf spotting to severe repeated dieback and death of affected trees. This is the first investigation into the impact of myrtle rust in regenerating Myrtaceae following wildfire and highlights a need for more detailed studies.