A plant louse is a tiny insect that feeds on plants by piercing their stems or leaves and sucking out the sap, the nutrient-rich liquid that flows through plants like blood flows through our bodies. These insects are more commonly called aphids.

Plant lice are surprisingly small: most are only about as big as a sesame seed. They come in various colors, including green, black, yellow, or pink, and they often gather in clusters on the undersides of leaves or along stems. Gardeners usually consider them pests because large groups can weaken plants, cause leaves to curl or yellow, and spread plant diseases.

Despite their small size, plant lice reproduce incredibly quickly: a single aphid can produce thousands of offspring in just a few weeks. This rapid reproduction is why gardeners often find their plants suddenly covered with these insects seemingly overnight.

Many beneficial insects, like ladybugs and lacewings, eat plant lice, helping to control their populations naturally. Some farmers even release these helpful predators into their fields as a form of natural pest control.