I've written a lot about myrtle rust, until last year it was relatively unknown.  It still surprises me that many who are involved in the plant industry don't know much about it.  It was introduced possibly via Hawaii from the USA where it was used as a biological control against myrtaceae that is a weed there.  Our native animal such as koalas are already becoming stressed by invasion and destruction of habitat.  More information Biosecurity Queensland 13 25 23 or go to www.biosecurity.qld.gov.au