Scales are usually found on stems and the undersides of leaves but can be on top of the leaves. Small infestations can be removed by touching each insect with a cotton swab dipped in alcohol. Soil insects are noticed when brought to the surface during watering. Adults and larvae of several insects may fly or crawl around on the soil surface. In most cases they do no real harm to the plant.
Large populations can cause wilting and poor plant growth due to minor root pruning.
Unfortunately, pesticides used to control soil insects may be as harmful to the plant as the insects. House plant diseases are not seen as often as insects. Diseases such as powdery mildew or various root and stem rots are encountered, but can be controlled to some extent with proper plant care. Most problems resembling diseases are the result of improper care.