Aphids infiltrate interior gardens, greenhouses and plant rooms and can come in through windows, doors and air vents or with infected plants. They conduct the same destructive activity indoors as they do outdoors, and the same aphids local to exterior spaces will colonize indoor spaces. Aphids are fairly indiscriminate in their taste for plants and will attack any plant with tender succulent growth. According to W.S. Cranshaw at Colorado State University, commonly seen aphids on indoor plants include the green peach aphid; melon, or cotton, aphid; potato aphid; and the chrysanthemum aphid.
Chrysanthemum aphids are dark mahogany brown with a shiny soft carapace. They are roughly 2.5 mm in length and are also commonly known as blackflies. They feast almost exclusively on this family of plants.
Green Peach Aphid
Green peach aphids are pale greenish-yellow in hue and attack a wide range of flowering and foliage plants, vegetables and fruit trees. They are between 1 and 2 mm in length and can spread more than 100 unique plant viruses as they travel about.
Melon, or cotton, aphids are most active in temperate and tropical climes. They are pale yellow or white in hue and roughly 2 mm long. They can be brought indoors by infected plants and spend the winter inside breeding to be re-introduced into uninfected plants outdoors in the spring, making them especially pernicious. They can reproduce in roughly seven days in warm indoor surroundings.
Potato aphids, known scientifically as Macrosiphum euphorbiae hemiptera, are brightly colored aphids that are either pink all over, green and pink or pale green with a dark stripe down the back. They have no wings and grow to be up to 3.5 mm in length. They infest and eat away at a wide variety of plants favoring vegetables, roses and weeds such as jimsonweed and ragweed.