House plants are often infested with mealybugs. These insects appear to be little tufts of cotton on the leaves and stems. They are most common on the undersides of leaves and at the point where a leaf attaches to a stem. The insects can be hard to control on plants where new leaves emerge from a sheath. The insects get inside the sheath so are protected from sprays. The fluffy appearance is due to white wax filaments. The wax will repel pesticides and makes the insects somewhat difficult to control.
Light infestations can be controlled by touching each insect with a cotton swab dipped in rubbing alcohol. House plant insect sprays will control mealybugs if the grower is persistent. Systemic insecticides will also give good control.