Known sometimes as thunderbugs, or corn lice, thrips are tiny insects that often invade flowering plants. They can occur in large numbers and invade homes, but usually, they are no more than a nuisance. Thrips are no more than 1/16th of an inch long and can be yellow, black or grey in color. Over 690 species of them exist in the U.S. and Canada.
The life cycle of a thrips usually occurs in 4 to 5 stages. One feature that is distinctive to thrips is that there are no males in many of the species. In spite of this fact, thrips are prolific breeders, reproducing 3-5 generations per year. The females lay single thrips eggs in plant leaves. Typically in a 2-4 week period, the thrips hatches. It is usually an inactive creature. Larva stages are the next two phases, where some thrips develop wings and others remain wingless. Life stages three through five are the pupa stages. Some thrips species have pupa that are almost dormant and do not feed. Some are winged in these stages and some are not. The adult phase follows the pupa stage, with external wings developed in a stage along the life cycle.
Thrips conceal themselves in flowers and leaves of plants and usually will feed on flower heads and leaves. Thrips eat by stabbing their mouthparts into the fruits or flowers of a plant to suck out the juices. Major pests of cultivated plants, thrips can become a serious problem for growers. Thrips can do major damage to citrus crops and other ornamental crops and, often, will swarm in large numbers.
Thrips usually enter homes or structures on cut flowers or houseplants, and will also bite humans. Thrips also can be found in clothing that has been outdoors, such as laundry, and they will bite humans when the clothes are worn. Thrips bites can be painful and can possibly develop into a rash.