Indoor plants, just like their outdoor counterparts, can suffer from the presence of pests. There are several common houseplant bugs that can be a nuisance, and some can seriously damage your plants. Guard against introducing these into your indoor garden by closely inspecting new plants before mingling them with others, and by regularly examining your existing plants.
Sometimes called "greenhouse whiteflies," these winged pests are commonly found on plants grown in a greenhouse environment. Whiteflies are not actually flies at all--they're more closely related to scales and aphids. The very small, moth-like insects are easily disturbed and may flutter up when the plant is moved. Whiteflies damage plants by sucking their sap, and excrete an unattractive sticky substance on foliage. Control options include washing the plant's leaves and spraying with insecticides. Winged adults can be vacuumed, as well.
Graying leaves may be a sign that your plant is infested with spider mites. These tiny pests are almost too small to see with the naked eye, but can cause serious damage and even plant death. To check for the presence of these pests, place a sheet of white paper under discolored leaves of your plant and tap. Tiny moving black specks on the paper are spider mites. They first feed on the underside of leaves, then expand their territory by moving around via a fine webbing. Spider mites thrive in warm, dry conditions, so you can protect your plants by increasing the humidity around them. Other controls include washing foliage and spraying with horticultural oils. Heavily infested plants should be disposed of, as they can be a source of new infestations.
Mealybugs are soft-bodied insects that suck the sap of plants. Some of their favorites include cactus plants and poinsettias. Adult female mealybugs produce a large amount of cottony material in which to lay their eggs, making their presence easy to detect. Sometimes this white substance is mistaken for powdery mildew. Some types of mealybugs attack plant roots below the surface of the soil. Controls include physically removing the bugs and eggs, spraying with alcohol or insecticidal soaps, and washing.