How Do Lacewings Help Control Garden Pests?

Lacewings are among the most effective and underappreciated predators in the garden. The delicate green adults with their gossamer wings look harmless, but their larvae — aggressive, alligator-shaped hunters also called aphid lions — can consume up to 200 aphids before they pupate. Lacewing larvae also eat thrips, whitefly, small caterpillars, and spider mites, making them genuinely broad-spectrum biological control agents.

Better still, they are free and already present in most gardens. Your job is to support rather than hinder them.

Understanding the Lacewing Life Cycle

Green lacewings (Chrysoperla spp.) overwinter as adults in sheltered spots — dense evergreen foliage, seed heads, insect hotels. They become active in spring and begin laying eggs on fine silk stalks on plant surfaces near aphid colonies. The eggs are distinctive: tiny white ovals on hairlike stems, clustered near shoot tips. The larvae hatch within a few days and begin feeding immediately, working through aphid colonies with extraordinary efficiency.

After two to three weeks of intensive feeding the larva pupates in a silken cocoon. Several generations occur each summer in warm years.

Providing Nectar for Adults

Adult lacewings feed on nectar, pollen, and honeydew. They are attracted to small-flowered plants with accessible nectar, particularly angelica, coriander, fennel, dill, and sweet alyssum. A patch of these near pest-prone beds acts as a holding area, keeping adults close to where you need their larvae. Phacelia and buckwheat are also highly attractive to lacewings and quick to establish from seed.

Overwintering Habitat

If adult lacewings cannot find safe overwintering sites in your garden they will leave and not return in spring. Dense ivy, bramble, or evergreen shrubs provide natural shelter. Alternatively, fill a terracotta pot with corrugated cardboard or straw, cap it with mesh, and hang it in a sheltered spot. Commercial lacewing hotels work well and are inexpensive. The investment pays off enormously come April when adults emerge ready to lay eggs on your early aphid infestations.

Buying Lacewing Eggs

If your lacewing population is low or you have a severe infestation that needs immediate reinforcement, lacewing eggs and larvae are commercially available. They are typically supplied on shredded material to be distributed through the crop. Results are fastest at temperatures above 15°C. Deploy as soon as you notice aphid establishment, before colonies peak.

Protecting What You Have

Pesticide use is the primary reason lacewing populations decline in gardens. Many contact insecticides and some systemic treatments kill lacewing larvae and eggs on contact. If your pest problem is severe enough to consider spraying, first confirm no lacewing larvae are already present — a few working larvae, given a week without intervention, can clear small colonies entirely.