One of my Banksia serata trees seems to have contracted pthytothera. I am going to cut the above ground part of the tree off at about 1 foot from the ground, and carefully dig up the rest of the below ground plant material and as much soil as i can and remove to landfill or burn. Can I chip and compost the above ground part of the Banksia without contaminating my compost ? Is my plan a good one?

Cheers
Mark