Dug some sweets today. Although all of the conventional literature says that “no variety is resistant to scurf“ my experience has been different. So far this year:
Jewell - no scurf seen
Ginseng Orange - severe scurf on about 2/3 of the larger roots.
In past years, I found Copper Jewel (similar root to Jewell but different foliage) also very resistant. It also seems like old varieties in general fare worse.