Aphids infest all manner of trees, shrubs, flowering plants and green plants. While not commonly found on houseplants, aphids can get on your indoor plants and damage them. While aphids rarely kill a plant, they do create a mess and weaken the plant's defenses, leaving it more vulnerable to other pests or diseases.
Aphids average 1/16- to 1/8-inch long and range in color from green to black, brown, yellow or purple, though green is the most frequent color. Aphids gather on the underside of leaves or beside flowers, or on newly opened or opening leaf buds and flower buds. Aphids create a sticky, slimy trail called honeydew that can be the most visible sign of an aphid infestation.
Rinse your plants under warm water to dislodge the aphids, using a hose or sink set to a high-powered spray. Pluck off and remove aphids with your finger. Alternately, create a solution of 1/2 tsp. dish soap mixed in 1 gallon of water. Then wash the leaves and stems of your houseplant with this soapy solution.
Gardeners have a range of options to use for chemically controlling an aphid infestation. Use neem or horticultural oil or an insecticidal soap. Purchase an insecticidal spray that contains bifenthrin, permethrin or resmethrin; spray your plant with this solution every seven to 10 days until you see no evidence of aphids.
Give your houseplants enough water, sunlight and air for their needs to keep them healthy. Regularly rinse or spray the leaves of your houseplants with water to keep them moist; insects including aphids prefer dusty, dry leaves.
Since aphids are less frequently found on houseplants than they are on outdoor plants, trees and flowers, gardeners should take care when bringing clippings in from the garden or when bringing houseplants indoors after letting them get sun outdoors for a while. Inspect the leaves and stems of any plants you move between indoors and outdoors.