Scale has a hard usually brown, sometimes gray or green, round to oval shell, looks like a small bump on a leaf, and can be found feeding on leaves, petioles (place where leaf connects to stem), or stems. They feed on the sap of the plant. They spread rather quickly so don’t treat scale lightly. Infested plants become weakened or stunted and begin to die.
Control: Isolate infected plant(s) and cover any tables or carpet, etc. that may receive any over-spray if using soap or oil sprays.
Begin treatment using cotton swabs dipped in a diluted alcohol solution to wipe them off gently. They are extremely slow and do not fly but you will need to be persistent for several weeks to get rid of them all.
Sprays of a mild soapy water solution may be effective but are generally reserved for soft bodied insects. You can give it a try if the infestation is further along than the above treatment will take care of and should be repeated weekly until infestation is gone. There are some plants whose leaves are sensitive to soaps in which case you will see small brown spots in the leaves after application and you should not repeat the procedure. Crown of thorns, Jade plants and Gardenias are some examples. Some ferns, palms and succulents may also be sensitive. You can test a small area first if unsure.
Insecticidal oils can be sprayed on the leaves, stems and flowers of the plant. They disrupt the feeding and kill the insect. You can test a small area first if unsure about leaf sensitivity.
Systemic insecticides are water soluble and only if necessary can be administered to the soil. The roots absorb the insecticide and the insect will feed on it along with the sap. Always read instructions on purchased products before use and be certain it is appropriate for the plant and the insect you have.