Use [item=163212] near the sources of corruption (purple void zones)
There are 5 places (caves/buildings) you can visit.
They have most of the nodes you need to clear.
/way Stormsong Valley 80.50 57.04 Dank Grotto
/way Stormsong Valley 83.61 53.93 Bleak Sepulcher
/way Stormsong Valley 81.64 50.29 Moldering Foyer
/way Stormsong Valley 82.08 44.74 The Profaned Reliquary
/way Stormsong Valley 86.58 51.98 Crumbling Chambers
Demo video: https://www.youtube.com/watch?v=mXmTmdtVkZI
Related questchain
Related achievement: About To Break