Mealybugs are one of the more serious problems of houseplants. There are many different types of mealybugs and virtually all houseplants are attacked by one or more of these insects. Male mealybugs are rarely seen, but are winged and can fly. Female mealybugs have soft bodies that appear to have segments, and are covered with waxy secretions, giving them a cottony appearance. The female may produce live young or may deposit hundreds of yellow to orange eggs in white cottony egg sacs. The young insects, called nymphs, crawl about the same plant or to nearby plants. Males do no damage because they do not feed and are short-lived. Female mealybugs feed by sucking sap from the plant. They take in more than they can use, and excrete the excess in a sugary fluid called honeydew, which coats the leaves and may drop to surfaces below the plant. This fluid may mar finished furniture. For more information about mealybugs, see Mealybugs.
Control of mealybugs on houseplants is difficult. Separate infested plants from those not affected. Spray infested plants with an insecticide containing pyrethrins that is labeled for use indoors, or take the plant outside and spray with an insecticide containing acephate. (For information on spraying houseplants, see Spraying Houseplants.) Repeat applications at intervals of 2 weeks and continue for a little while after it appears that the mealybugs have been controlled. The waxy coverings on the insects and on the egg sacs, and the tendency of the insects to group together, protect them from insecticides. If only a few mealybugs are present, wipe them off with a damp cloth, or use cotton swabs dipped in rubbing alcohol. Carefully check all parts of the plant to make sure all insects are removed. Search for egg sacs under the rims or bottoms of pots, in cracks or on the undersides of shelves, and on brackets or hangers. Wipe off any sacs; they are a constant source of new insects. Discard severely infested plants, and avoid taking cuttings from such plants. The growing area should be thoroughly cleaned with soapy water before starting new plants. Be on a constant vigil for mealybugs, and start control measures immediately if they appear. Inspect new plants thoroughly before putting them in the house.
