They suck plant juices and heavy infestations will coat the leaves with sticky honeydew. Use house plant insect 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. 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.