The green lacewing (Chrysoperla spp.) is a beautiful and delicately-built insect in the adult stage. The body is about 1/2” long, slender and a pleasing light green to yellowish green in color. The wings are clear with pale green veins and are slightly iridescent. The adults feed primarily on nectar, pollen and honeydew. They have yeast in their digestive tracts that aid in breaking down nutrients from these food sources. Adult green lacewings are prey for a number of other animals including bats, birds and predaceous insects. They have good hearing, with hearing organs located at the base of the forewings. When they detect the ultrasonic signals of bats searching for prey, they exhibit defensive behavior by closing their wings in mid-flight and dropping to the ground. Their green coloration helps them hide from predators among plants.
Female lacewings lay 100-200 eggs during their life span of about six weeks. They tend to place the eggs where there are prey present for the young larvae to feed on. Eggs may be found on the underside of leaves, singly or in clusters, and each egg is borne on a stalk, giving them a balloon-like appearance.
Eggs hatch 3-6 days later and the larvae are voracious predators, feeding on other insects including aphids, mealybugs, scales, psyllids, thrips, whiteflies, small caterpillars, leafhoppers and insect eggs. They also feed on mites, particularly the red spider mite. ‘Aphid lion’ is a common name sometimes used for the larva. They have strong, hollow jaws used to inject a digestive saliva into the prey. This saliva is able to digest the internal organs of an aphid in only 90 seconds! The larva then sucks the juices from the preys’ body. As many as 200 aphids or insect eggs may be consumed in only a week. Debris including prey’s remains adheres to bristles on the larva’s back, helping to camouflage it from predators. The larvae look a bit like tiny alligators with a flattened body that has mottled coloring made up of light yellowish brown to darker gray markings. They have a tapered tail and visible legs.
Larvae feed for two to three weeks and then pupate within a spherical cocoon attached to a plant or under loose bark. Adults emerge in one to two weeks depending on temperature and humidity. The green lacewing may overwinter in various life stages depending on weather severity.
Green lacewings are available commercially for use as biological controls in the greenhouse, field and garden. They are generally affordable and are available as eggs, larvae and adults. If you are interested in establishing a population at the beginning of the season, eggs would be a good choice. For an existing problem, larvae will arrive hungry and ready to go. Adults can also be ordered and they are a good choice when treating a large area or if you don’t want to spend much time distributing eggs or larvae.
Some attractive characteristics of green lacewings as part of an integrated pest management (IPM) program include: 1. It’s broad range of prey (generalist), 2. It has excellent searching ability, 3. Some species are tolerant of insecticides, and 4. The adults will disperse readily. One little downside is that the larvae will also eat some beneficial insects and can be cannibalistic too. They will feed on the pests if that’s what is available!
You can attract natural populations of green lacewings to your garden by planting flowers that are attractive food sources for them. Suggestions include members of the family Asteraceae such as Coreopsis, Cosmos, and sunflower and the family Apiaceae such as dill and angelica. The common dandelion, milkweed, spotted joe-pye weed, Queen Anne’s lace, red clover, and bushy aster are other attractive plants for food and/or shelter.