Mealybugs are about the same size as aphids but are white and fuzzy. Masses of them, resembling pieces of cotton, nestle and lay eggs where leaves and branches attach to stalks. Mealybugs can stunt and kill plants by depleting their fluids. White flies also are small and white, but unlike mealybugs, will take flight if you shake the plant. They come in quantities and can spread to all the plants in your house.
Spider mites are miniscule but very destructive.
An infested plant will have yellow-speckled leaves and may be covered with tentlike webs. They're easy to spot if you hold a piece of white paper under the plant and shake the leaves so the mites drop onto the paper. Scale appears as blister-like areas on stems and the undersides of leaves. Scale also produces honeydew, which may drip from the leaves. Rinsing the plant under a gentle stream of water for a few minutes can wash away insects and eggs.