Lacewings

Updated by Rebecca Schmidt Jeffris, USDA-ARS August 2024. Original page by Rob Curtiss and Steven Booth, originally published 1993 and revised online December 2007.

Green lacewings

Chrysoperla johnsoni Henry, Wells & Pupedis
Chrysoperla plorabunda (Fitch)
Chrysopa coloradensis Banks
Chrysopa nigricornis Burmeister
Chrysopa oculata Say
Eremochrysa spp.
Meleoma dolichartha (Navas)
(Neuroptera: Chrysopidae)

Brown lacewings

Hemerobius humulinus Linnaeus
Hemerobius neadelphyus Gurney
Hemerobius pacificus Banks
Hemerobius stigma Stephens
Micromus variolosus Hagen
(Neuroptera: Hemerobiidae)

The lacewings listed here, and other less common species, are important natural enemies native to the Pacific Northwest. Green lacewings are widely distributed and are important generalist predators. They are often abundant in orchards where IPM is practiced and feed on a variety of insects. Although less well known, brown lacewings can also become abundant in orchards where soft pesticide programs are used. Lacewing larvae are active earlier in the season than many other predators and are good biological control agents for early season pests. Inundative releases of lacewings (Chrysoperla species) have been used to control mealybugs and variegated leafhoppers in California vineyards. In Washington, lacewings are released by growers for aphid control in apples.

Prey

Both green and brown lacewing larvae prey mostly on aphids but also attack scale insects, mealybugs, leafhoppers, thrips, mites, pear psylla and many other small sedentary insects. Brown lacewing and Chrysopa adults are also carnivorous, but adults of Chrysoperla species feed on aphid honeydew and plant fluids.

Life stages – Green lacewings

Egg

The egg is oval, green, white, or gray and is suspended on a long, hair-like stalk. Eggs become more gray as they are about to hatch. The egg is about 1/50 inch (0.5 mm) long, while the stalk is about 1/4 inch long (6 mm). Eggs are laid singly or in groups.

Larva

The larva’s alligator-shaped body is yellow or mottled gray with red or brown and has clumps of bristles. Its prominent sickle-like mandibles, or jaws, are longer than the head and are used to capture the prey and extract the body juices. There are three larval instars and larvae are about 2/3 inch (15 mm) long when mature. Chrysoperla larva found in orchards have two prominent marks on the head capsule, whereas Chrysopa have three.

Pupa

The larva pupates in an opaque, white or yellow, tightly woven, spherical cocoon, often in leaf litter, soil, or under tree bark. The pupa is green with many features visible externally. Pupae are rarely observed in the field.

Adult

The adult is mostly green with gold markings and large, lace-like wings. It is about 2/3 to 3/4 inch (15 to 20 mm) long. Its flight is fluttery and weak. Chrysoperla adults have a yellow/light green stripe running down their back and often have red markings on their gena (“cheeks”). Chrysopa adults do not have a stripe and often have black head markings.

 

Life stages – Brown lacewings

Egg

The egg is pink, white, or cream-colored and does not have a stalk. Eggs are attached to the leaf surface and are less noticeable than green lacewing eggs.

Larva

The body is alligator shaped but narrower than that of green lacewings. It has few bristles, and the mandibles are shorter than the head. It is white at first but turns brown as it matures.

Pupa

The cocoon is loosely woven and transparent.

Adult

The adult is brown, beige or dark green with lace-like wings covered with hairs. At 3/8 to 1/2 inch (10 to 12 mm) long, it is smaller than the green lacewing.

Life history

Most lacewings complete 3 or 4 generations per year in the Pacific Northwest. Because different species develop at different rates, all life stages may be present during the late season. Chrysopa overwinter as third instar larvae (prepupae) within cocoons, Chrysoperla overwinter as adults, and brown lacewings overwinter as adults and larvae. Adults emerge in early spring and disperse. Breeding continues throughout the summer. Brown lacewings in the genus Hemerobius are often among the first predators to emerge from overwintering locations in the spring and can be active predators even when temperatures are relatively low. Chrysoperla adults and larvae are found earlier in the season than Chrysopa, but Chrysopa are almost always much more abundant.

Monitoring

Lacewing adults and larvae can be monitored in orchards with beating trays. The active adults are best sampled in the cool morning hours. Scouting for adults with beat trays may be supplemented with sticky cards. The number of lacewing larvae needed for effective pest control has not been established. Larvae can also be detected by examining active aphid colonies on the undersides of leaves, although this may underestimate their activity in the orchard. Eggs are usually laid near aphid colonies and can be monitored at the same time as the larvae.

 

Management

Lacewing adults will move into the orchard from uncultivated vegetation. To augment local populations of lacewings, preserve unsprayed vegetation near the orchard. Eggs, larvae, and adults of Chrysoperla spp. are available commercially for mass release. Many different species are sold as “Chrysoperla carnea”, including native C. plorabunda. Chrysoperla rufilabris, an east coast species, is also available, but does not appear to be able to overwinter and establish in orchards. Because of the tendency of adults to disperse after they emerge, releases of eggs or larvae are more effective than adults. Adults of most species are attracted to honeydew rather than the pest. Releases of larvae are typically more effective than eggs because the larvae begin feeding on pests immediately, whereas there is a delay in biological control while eggs hatch. Eggs are also more likely to be eaten by other orchard predators. High ant populations will disrupt biological control by both resident and released lacewings.

Lacewing Gallery