Spider mites, mealy bugs, aphids! Indoors? How did those pests get in here?

You opened the doors. You opened the windows. They drifted in on the breeze.

You carried them in on a bouquet from the garden or on a newly purchased plant.

You carried them in your person, or they rode in on your pets.

So, what can you do?

You can inspect your houseplants regularly so that these unwelcome freeloaders don't have a chance to settle in. If you discover they have already arrived unannounced, here are some suggestions for asserting your dominance.

Plants on which pests are discovered should be isolated so that the pest can't move on to ever greener pastures on other plants in your collection.

A mild infestation can be overcome by washing plants once or twice a week in warm soapy (not detergent) water (1 tablespoon Ivory Flakes to 1 gallon of water). Let the plant dry. Rinse with clear water. Cover the soil around the stem of the plant with a collar of aluminium foil to prevent soil from washing out of the pot. Syringe or dip the whole plant. Use a soft brush to scrub the offenders off leaves and stems. Do not set the wet plant in the sunlight.

That good old-time remedy. Black Leaf 40 (nicotine sulfate) is still an effective pesticide even though newer materials such as malathion have come into use. Nicotine kills on contact with the pest.

If you do not object to use of insecticidal sprays, select one that is formulated for houseplants. Some insecticides are not for use on plants they contain oils or other chemicals lethal to plant life. Note the manufacturer's recommendations as to the plants on which the product can be used and follow label directions regarding use and precautions.

The commonest of the troublesome pests and some suggested controls are:

Mealybugs - furry, cottony, slow-moving, they concentrate in angles of stems and on veins of leaves. Hand pick them. Lift them off with a cotton swab dipped in alcohol, rinse with clear water. Use a malathion spray or Black Leaf 40.

Arphids - on young tender growths and flower buds, these minute pink, white, or black pests suck the juices; sticky deposit on plants and tables. Use the soap and water treatment once a week until no more aphids are seen. Use a malathion spray or Black Leaf 40.

Spider mites - a fine webbing on underside of leaves and in leaf axils is evidence of spider mites, though you may never see the pests; leaves may become mottled and dull. A strong spray of water on plants sturdy enough to withstands it will break up the webbing. Less rugged plants can be sprayed at the kitchen sink. Apply a miticide such as Kelthane according to instructions on the package label. Dip the plant or spray with malathon. Be sure to treat underside of leaves. Several treatments as weekly intervals may be necessary to finish off these invaders.

Scale - under those waxy-looking lumps are the real culprits causing yellow leaves and leaf drop, wilting, and a sticky deposit on the plant. Scrape them off with fingernails; pick them off with tweezers. Brush them off with a toothbrush dipped in soapy water. Use the soap and water and rinse treatment once or twice a week. Spray with malathion - except ferns. For ferns use Black Leaf 40. Always use extreme care in handling pestcides. They are poisonous. Malathion, besides being toxic, has an offensive odor and should really be used outdoors.

The best preventive is regular care.