Clubroot's a common disease of cabbages, radishes, turnips and other plants belonging to the family Cruciferae (mustard family). It's caused by Plasmodiophora brassicae, which was once considered a slime mold but's now put in the group Phytomyxea. It's as many as nine races. Gall formation or distortion takes place on latent roots and gives the shape of a club or spindle. In the cabbage such attacks on the roots cause undeveloped heads or a failure to head at all, followed often by decline in v… (More on Clubroot)