House plants are widely grown for ornamental purposes and enjoyment. Aphids (Homoptera) can often pose a problem for house plants. The saliva from the aphid has a toxic affect on new plant growth. Leaves will curl, turn yellow, distort and drop from the house plant that suffers from a severe infestation. Aphids feed on a large variety of commonly grown indoor plants and herbs.
Aphids measure 1/16-inch to 1/8-inch in length. The tiny insects are often called 'plant lice' due to their exceptionally small size. Aphid colors are white, green, gold, light red or brown. Many aphids appear waxy or almost woolly upon magnification. Their soft body has six tiny legs and appears pear-shaped. There are winged and wingless aphid varieties in a colony.
Aphids feed on house plants by piercing the stems and leaves of the plant with their razor-sharp mouths. Once a firm suction is established and penetration of the plant's flesh has been obtained, the insect begins to suck the sap from the plant. Aphids prefer to feed off the delicate new growth of the plant because the stems are softer and easier to penetrate with the insect's mouth. While the aphid feeds, its mouth injects saliva that contains toxins to help the sap flow freely into the aphid's mouth. The toxic saliva can cause the leaves of the plant to die and fall off.
House plants become infected with aphids when adult aphids fly onto the plant and begin to multiply. Aphids reach sexual maturity in only seven to 10 days and then are capable of reproducing. One female aphid can give birth to up to 60 young. Soon a large colony of aphids forms on the house plant. Once the aphid population explodes, winged aphids are produced to ensure the spread of the colony to new plants. The winged aphids leave the colony to establish new colonies elsewhere.
Aphids excrete a substance called 'honeydew' as they feed and live on the house plant. Honeydew is an ideal breeding grown for a fungus known as 'sooty mold'. Sooty mold can turn the leaves of the house plant black. Honeydew can also attract ant infestations on house plants because ants enjoy feeding on the aphid's sweet excretions.
Control of aphids on house plants can be obtained by washing the plant in a sink or the shower using an insecticidal soap. Numerous types of contact insecticide sprays are available for use on house plants that suffer from aphids. Follow the directions on the label for application.