If your houseplants have brown, crusty patches, or look like someone sprayed them with soda pop, your plants may be infested with scale insects. These insects, from 1/16 to 1/4 inch wide, feed on sap, hide under a shell-like coating, and secrete honeydew, the clear, sticky fluid on plants. If untreated, scales can spread to other plants.

Signs to look for:
Crusted or spotted patches on stems and leaves. Close up, look for tiny bumps--the scale insects. They're usually on the underside of leaves.

Honeydew, which looks like dried soda pop. It may attract a black, powdery fungus called sooty mold. (Sooty mold doesn't harm plants, but it does block light from getting to the plant leaves.)

Pale, discolored leaves. Along with discolored spots and honeydew, sickly leaves indicate that scale insects are sucking your plant's sap.


Remedies:
Throw away badly infested plants and quarantine treatable ones.
Scratch scale insects from plants with a fingernail, toothpick, or tweezers.

Swab scale insects with rubbing alcohol (do this at least once a week for several consecutive weeks).

Use insecticidal soap (again, at least once a week for several consecutive weeks). Be sure to spray the soap where you see the insects; if they're on the bottoms of the leaves, spraying the soap on top of the leaves won't help.