The majority of Australia’s unique flora has evolved in isolation separated from many of the world’s major plant pathogens. As these pathogens have made their way into Australia the impact on plant species, ecological communities and the fauna that depends on them has been dramatic. Two plant diseases, Phytophthora root rot and Myrtle Rust, are used as examples to illustrate the impact diseases can have on fauna. As animals are either explicitly or implicitly dependent on plants for their survival the deleterious impacts of plant diseases on flora inevitably flows onto animals either limiting food resources, habitat or shelter for reproduction. The consequences, particularly for fauna already under threat, are that plant diseases will not only push plants towards extinction, but also those animals dependent on them.