Thrips, also known as corn lice, or thunderbugs, are tiny insects that often invade flowering plants. Usually, they are no more than a nuisance but they can occur in large numbers and invade homes, as well as ruin crops. Thrips are less than 1/16th of an inch long and can be black, grey, or yellow in color. More than 690 species of them exist in the U.S. and Canada.
Thrips conceal themselves in parts of plants and usually will feed on flower heads and leaves. These insects insert their mouthparts into the fruits or flowers of a plant and suck out the juices. Thrips are a chief pest of cultivated plants, and this can be a problem for growers. In addition, they will bite humans and can enter homes or structures on cut flowers or houseplants. Thrips also can be found in garments that have been outdoors, such as laundry, and they will bite humans when they wear the clothes. A thrips bite can be painful and may develop into a rash.
Recently, a species of thrips has been found where none were before. The South African citrus thrips has become a troublesome pest in Australia, feeding on the succulent crassulaceae. Members of this plant family include ornamental plants, such as the jade plant. This type of plant has not been one that thrips have fed on before. Agricultural experts believe these South African citrus thrips were brought in on infected plants or were blown in to the area by stormy weather.
Thrips will swarm in large numbers and can do major damage to citrus crops and other ornamental crops. They are productive breeders, despite the fact that they reproduce without fertilization, and manage to hatch 3-5 generations per year.