Sometimes, the tiny crawling or flying bugs that you see in your home may be coming from your very own house plants. For example, you may find a floor or tabletop that has crawling spider mites or sticky honeydew, or white flies or fungus gnats may fly off of an infested plant if it is bumped, eventually settling back onto the leaves or soil. You may not connect these insects with the plant.

Often, plants are already infested when you buy them from the nursery or the grower. An early infestation may not even be visible at that point. Plants can also become infested when they spend time outdoors. When plants are brought back into the drier indoor conditions in the fall, pest infestations can explode.

Plant-sucking pests are usually found on the underside of the leaf. At first glance, the plant may look fine. Turn over a few leaves. It will help to have a magnifying glass. You might find:

• insects or mites moving about, or tiny white eggs, pupal cocoons, or black fecal specks on the bottom of the leaves.
• sticky droplets of “honeydew” sap exuded by the pests on the leaves, or a gummy feel on the surface below the plant. Ants may be attracted to the honeydew.
• thin webbing spun between the stems by spider mites. Look closely for tiny mites moving along the webbing.
• stippled leaves covered with tiny yellow or white feeding punctures. Eventually, the leaves will turn pale, coppery, or silvery, and may drop prematurely.

Can your plant be saved? There are many different treatments for infested plants, but they aren’t always successful. If you don’t particularly value the plant, or if it seems too far gone to save, it’s best to simply throw it out. You run the risk of infesting any other indoor plants as well.