Does anyone know how to effectively get RID of scale insects? My two spider plants (which are in two different rooms) and my purple passion plant have scale insects. I pick them off with my finger nails often, but it still seems to be a problem. Also, on a side note, does anyone know why only these plants are affected? My purple passion is close to about 4 other plants, a night blooming cereus, a draceana, and rope hoya, and a christmas
cactus. These have all been friends now for about a year and a half and it's never been a problem for them thank goodness! Thanks guys!