Posted: 21/06/2013 at 16:08
I actually don't think it's in your soil. This bacterial disease is transmitted by rain, wind, birds and insects so "it's in the air", and can infect trees even through the stomata. We've had some very wet seasons and so, unfortunately the circumstances have been ideal for the disease to spread that quickly.
Please, do contact a tree specialist if you can or look for a knowledgeable fruit tree grower. They will be able to tell you if your trees can be saved and what precautions to take now and in the future. I will keep my fingers crossed for you!