There are not many true diseases which attack cacti and succulents. Damping-off disease (damping-off disease) only affects young seedlings as a general rule, and is dealt with the special seed-raising section at the back of the book. Orange rot occurs in a few American cacti, particularly certain Ferocacti, where it usually starts at the root; the only solution is to cut it out, dry the plant off and re-root, treating as for "cuttings".