White leaf spot (Cercospora or Cercosporella spp.)
Leaf spot diseases caused by these two fungi are similar in their symptoms, biology, and damage. Cercospora has been more frequent in recent years, but both are probably present. White spot is most severe on turnip, mustard, and turnip x mustard hybrids. The disease is less important on collards and kale. The fungi persist on infested crop residue and possibly wild crucifer weeds. Spores from debris, weeds, or neighboring fields become airborne and are blown to new fields.