Mealybugs look like white puffs of cotton. They suck plant juices and heavy infestations will coat the leaves with sticky honeydew. Use house plant insects sprays according to label directions.
Mites are very small and are hard to see without a magnifying glass. Heavy infestations can cover the leaves with very fine webbing. The plants gradually lose their green color and appear dusty or speckled. Use a house plant insect spray according to label directions.
Aphids suck plant juices and are usually found at the stem tips. A heavy infestation will coat the leaves with sticky honeydew. A black, sooty mold can grow on the honeydew. The insects can be green, white, pink or black.
Scales are usually brown, hard shells attached to the stems or undersides of the leaves. Sprays are not effective since the shell protects the insects. Heavily infested plants should be discarded. Physically removing the scales and then controlling immature stages with sprays may control the problem on lightly infested plants.