The radiator hose may be breaking down and the reinforcing fabric may be wicking up the coolant. What you could be seeing is the crystallisation of the coolant after the water has evaporated. Wipe it away and check the end of the hose.
I had this happen on a Triton I owned. It didn't look as bad because it had a green coolant so my build-up was lime green.
I could be wrong but hopefully it's something as simple as this.