Dusty Miller
Symptom Cause  
Leaves wrinkled or curled; discolored, stunted, tend to fall off
Flowers yellow/green/deformed; spindly
Aster Yellows
Plant actually disappears
Green plant colors, wilts, tans; pink mass on roots; plant dies
Fusarium Wilt
White powder coats top of leaves
Powdery Mildew
Leaves yellow, wilt, die
Stem Rot