Mealybugs look like cottony blobs on the stems and leaves of houseplants. Look for them when leaves begin to yellow and wither. If a plant is small, dip the stem and the leaves into warm, soapy water.
Rinse thoroughly 2 hours later. For a larger plant, moisten a cotton swab in rubbing or denatured alcohol and use it to remove the mealybugs one at a time. Try not to get too much alcohol on the plant. Rinse the plant thoroughly with water. Control a severe infestation with a spray of malathion or with nicotine sulfate.
If a plant appears stunted, mealybugs may be on the roots. Wash the soil from the roots in lukewarm water, cut away infested parts, and soak the roots in a malathion solution. Repot in clean soil. Don’t use malathion on cacti and ferns.