Several species of green lacewing are found in gardens and field crops in Colorado. Lacewing larvae are voracious predators capable of feeding on small caterpillars, beetles, and soft-bodies insects such as aphids. The adult stage is familiar to most gardeners as they typically have a pale green elongated body with large, clear, highly veined wings that are held over the body when at rest. Adults are typically 19 mm (3/4 inch) long. The adults of some species are predatory, while those of other species feed on honeydew, plant nectar, and yeasts.
Lacewing larvae are usually cream to yellow colored and resemble larvae of lady beetles. They also have rows of black, brown, or reddish spots that extend the length of their abdomen. Green lacewing larvae are usually 13 mm (1/2 inch) long and have mouthparts that extend from the head and curve inwards.
Eggs of green lacewings are elongated and 1.5 mm (1/16 inch) or less in length. Eggs are laid singly at the end of a silken stalk that is attached to plant structures. The eggs are yellow, green, or white before changing to blueish-green and gray before hatching.
- There are about 85 species of green lacewing in North America. One species, the goldeneyed lacewing (Chrysopa oculata), is commonly found in hemp fields in Colorado.
- Adults and larvae can be beneficial predators of insect pests, and larvae are the commercially available life stage given their high effectiveness as predators.
- Lacewings are commercially available for purchase and can provide effective biological control of pests, particularly in small-scale production systems and greenhouses. When releasing green lacewing larvae, controlling ant populations is important since green lacewing larvae will hide in debris to avoid being eaten by ants, who often protect aphids in exchange for honeydew.
Adult green lacewing. Image credit: Whitney Cranshaw, Colorado State University, Bugwood.org
Green lacewing egg on a hemp leaf. Image credits: Whitney Cranshaw, Colorado State University, Bugwood.org
Green lacewing larva. Notice the mouthparts protruding from the head. Image credits: David Cappaert, Bugwood.org
Container of live green lacewing larvae. These products are commercially available for control of various insect pests, especially small soft-bodies insects such as aphids. Image credit: Joseph LaForest, University of Georgia, Bugwood.org
Life history and habits
Green lacewings develop through four life stages: egg, larva, pupa, and adult. Green lacewings lay eggs singly on a stalk to prevent newly hatched larvae from cannibalizing each other. Eggs hatch after 5-6 days and newly hatched larvae begin searching for prey, and the larvae feed and develop for 2-3 weeks. Pupation occurs in a protected area on the plant in an oval shaped cocoon, which also serves as an overwintering chamber for late-season pupae. The following summer, an adult will emerge from the cocoon and begin feeding and reproducing. Green lacewings typically produce several generations per year.
Larvae use their sickle-shaped, sharp mouthparts to suck body contents out of their prey. The adults of certain green lacewing species are predatory and primarily feed on aphids, which helps to control infestations and decrease the amount of honeydew excreted, which in turn decreases the chance of sooty mold growth.
Applications of broad-spectrum and persistent insecticides or miticides should be avoided. Controlling ant populations will increase the effectiveness of green lacewings, especially against aphid infestations since ants will often protect aphids in exchange for honeydew. This is especially important when releasing green lacewing larvae as biocontrol agents since they tend to hide in debris to avoid the ants.
CSU. (n.d.). Green Lacewings. Colorado State University – Extension. Available https://webdoc.agsci.colostate.edu/hempinsects/PDFs/Green%20Lacewings%20with%20Photos.pdf
UCIPM. (n.d.). Green Lacewings. University of California Agriculture and Natural Resources. Available https://ipm.ucanr.edu/natural-enemies/green-lacewings/
Varenhorst, A. 2023. Green Lacewings: Beneficial Predators for Both Small and Large-Scale Landscapes. South Dakota State University – Extension. Available https://extension.sdstate.edu/green-lacewings-beneficial-predators-both-small-and-large-scale-landscapes