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.
Whitefly is named for the adult, a small, white fly. The immature whitefly is a small, almost translucent scale- like insect. This insect is hard to control. Use a house plant spray specially formulated for whitefly.