Aphids are tiny soft-bodied pests that feed on a variety of plants, including vegetables, ornamentals, trees, shrubs, and houseplants. Because they reproduce quickly and have multiple generations per season, their populations can explode within a few days.
Aphids inject their mouthparts into the plant tissue to feed on the sap. “When there is a large number of aphids, you may see deformed or discolored leaves or stunted plant growth,” says Khan. “Some aphid species are specialists that feed only on certain plants, while others are generalists that feed on many different types of plants.”
Aphids also can be vectors, or transfer, pathogens to some plants. “Unfortunately, by the time you notice them feeding, they’ve already transmitted the disease,” says Bertone. “They excrete honeydew, a sticky substance that attracts ants, which also keep aphids’ natural predators away.” Honeydew may lead to a buildup of sooty mold, a type of fungus. If the plant becomes covered, the fungus can interfere with the plant’s ability to photosynthesize, which can affect its growth, says Khan.
Getty Images / Christophe Lehenaff
There are a few ways to manage aphids in your garden and on houseplants, but you’ll need to combine these techniques for the most effective control, say Khan and Bertone.
These insects are found in colonies, clustered on the undersides of leaves and stems. They’re oval or pear-shaped, usually about 1.5 to 2.5 mm in length. They have three pairs of legs, antennae, and a pair of tailpipe-like structures, called cornicles, on their back ends, says Bertone. They may be yellow, pale green, dark green, red, black, or covered with white, waxy filaments that resemble wool.
Aphids have a complex life cycle, which is why the population can skyrocket within days. The eggs, which are minuscule, overwinter and hatch in spring when temperatures warm up. All of these aphids are females that give live birth to other females. When food runs out or things get overcrowded in a location, winged females are born and fly off to other plants. As cold weather approaches, both female and male aphids are produced to mate, with females laying eggs that start the cycle all over again.
