Myrtle rust is an invasive fungus that infects iconic native New Zealand trees in the Myrtaceae family, such as pōhutukawa and mānuka.
It was first detected in New Zealand in March 2017 and is now found throughout the upper North Island. It has currently been recorded as far south as Greymouth.
Austropuccinia psidii, the fungus that causes myrtle rust, is known to reproduce by cloning itself (making identical copies), but a new study has now found evidence that it is also able to reproduce sexually. This sexual recombination of genes means that the fungus has a better chance of overcoming natural plant resistance as well as being less easy to control by biological or chemical means.
“Sexual reproduction creates new individuals with new genotypes, allowing the fungus to adapt to host defences,” says Stuart Fraser, a researcher from Scion who is one of the authors of the study, published in the European Journal of Plant Pathology. “Sexual recombination also allows it to adapt to new environments and new host species.”