Recently I attended the 2009 Dieback Information Group Conference - what an eye-opener for people living in Perth!
Did you know that Dieback is caused by a microscopic organism called Phytophthora cinnamomi? This rampant and aggressive little beast has caused severe damage to thousands of hectares of bushland in WA. Unfortunately, a lot of bushland had been damaged before Dieback was properly identified. Dieback kills many species of trees and shrubs. Plants that are susceptible include banksias, grasstrees, jarrah, she-oaks and hibbertias. Dieback is commonly spread by movement of infested soil by vehicles, but can also hitch a lift in gravel or mulch.
But it's not just a bushland problem... many exotic plants (including avocado, oak, pines, roses, camellia, azalea, grapes, apricot, peach and macadamia) are also susceptible. That means that orchards, nurseries and private gardens are potentially at risk.
Since there's no cure, the best approach is PREVENTION. Many bushland areas now have signage showing infested and non-infested areas. There are hygiene protocols to stop the spread of Dieback, such as not going into infested areas, and cleaning boots and vehicle tyres/chassis after using bush tracks. If you think you've been walking in an area that has Dieback, clean the soles of your boots with metho when you are leaving the area. Then you won't take the disease home to your garden.
I would add - be very wary of bringing home infested soil, gravel, mulch or plants for your garden. Please note that some nurseries or garden suppliers may not be checking their stuff to see if they have Dieback. You might be bringing home a heart-breaking problem.
Sadly, some natural heritage areas of WA have been damaged beyond repair by Dieback. The good news though - not all plants are susceptible. And if we all work together, we can halt the devastation.
If you want to find out more about Dieback, please have a look at the Global Invasive Species Database, and WA's Dieback Working Group website.