The larva of the green lacewing bug is a voracious predator of soft-bodied pest insects including aphids, whiteflies, and the caterpillars of many pest moths.
One lacewing larva—also known as an aphid lion—can devour 100 aphids in a week. One or two or three larva in each square foot of a garden can rid the garden of almost all soft-bodied pests in two to three weeks.
Lacewings can be attracted to a garden by nectar producing flowers such as Queen Anne’s lace, coreopsis, cosmos, sunflowers, dill, and angelica. Lacewings are also attracted by a yeast-sugar water mix called Wheast. Green lacewings are commercially available and among the most commonly released predators or beneficial insects.
Here is an overview of the common green lacewing:
Scientific name: Chrysopa spp., Chrysoperla spp.; of the family Chrysopidae.
Range: Various species throughout North America and Europe.
Life cycle: Adult lives 4 to 6 weeks; females lay eggs; Eggs hatch within 3 to 4 days; Larva develops over 2 to 3 weeks, then puates spinning a cocoon; Adult emerges from the cocoon five days later.
Description of adult: The green lacewing has delicate features: a bright green to pale green to greenish-brown smooth body, and four, transparent and slightly iridescence wings with a fine network of visible veins. The delicate long green wings are ½ to ¾ inch long (6 to 65 mm). The lacewing has knobbed antennae, and many species have golden eyes. Adults have chewing mouth parts. The adult lacewing is sometimes called a stink fly because it can emit an unpleasant odor when handled. An adult lacewing lives for 4 to 6 weeks; a female can lay as many as 1,000 eggs before dying. Adults are nocturnal flying about during the cool of the evening and early morning hours; they are attracted to bright lights.
Larva: The lacewing larva or nymph is yellowish gray with brown marks, tufts of hair, and a long jaw with curved mandibles that pinch together; it looks a bit like a tiny alligator. The larva grows to about 3/8 inch long. The larva is a voracious predator attacking soft-bodied insects such as aphids and caterpillars of like or smaller size. The larva uses its maxillae to seize and pierce prey and inject paralyzing venom; it then sucks body fluids from its prey. The larva can suck the life juice from an aphid in 90 seconds and can eat 100 aphids or more in a week. A larva develops over two to three weeks then pupates by spinning a silky white cocoon; an adult emerges five days later. and four to six weeks and repeat the life cycle.
Eggs: Lacewing eggs are oblong and white or green. Eggs are laid singly attached to the underside of leaves by a threadlike filament. Eggs are often laid on the leaves of plants infested with aphids. Eggs are deposited at night and hatch within a few days. The filament keeps emerging young larvae from eating each other after they hatch. The tiny predatory larvae begin eating soft-bodied insects such as aphids immediately. The larvae are known as aphid lions eating 100 aphids or more before they pupate. Larvae or nymphs live 15 to 20 days before pupating.
Life cycle: There can be three to four generations or more of lacewings in a growing season depending upon the length of the warm temperature season. They emerge from cocoons and begin adult life when the air temperature ranges between 65°F and upper 80s. Lacewings pass the winter in the pupal stage, cocoons. All stages of lacewings can survive mild winters.
Feeding habits: Adult lacewings feed on pollen, nectar, and honeydew (the excrement of aphids and other sucking insects). Many adults also prey on aphids, various larvae, and the eggs of other insects. Lacewing larvae feed an aphids, young corn earworms, mites, young scale insects, whiteflies, leafhoppers, thrips, and eggs of most caterpillars, and other small pests. Lacewings do most of their hunting at end of the larval stage.
Host plants: Adult lacewings feed on the pollen and nectar of wild carrot, Queen Anne’s lace, Queen Anne’s lace, coreopsis, cosmos, sunflowers, dill, angelica, and oleander. Adult lacewings are also attracted to an artificial diet called Wheast, one part sugar and one part brewer’s yeast in water. Use host plants or Wheast to attract and keep lacewings in the garden.
Coverage and release: You will need 1,000 lacewings to cover a garden of 1,000 square feet. Lacewings are commercially available and are commonly shipped as eggs. Place 1 to 3 eggs on each plant; not more densely or the larvae will eat each other. Eggs should be lodged gently in the crevices of leaves or flower petals or sprinkle the larvae around the garden. Release new lacewings every 10 to 15 days.