Integrated Pest Management Guide

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LACEWINGS

GREEN LACEWINGS (NEUROPTERA: CHRYSOPIDAE)

Green lacewings are often seen on cranberries and on trees, shrubs and other low-growing plants in the vicinity of cranberry beds. They have large membranous green wings, golden- or copper-coloured eyes and are active predators at night. The large green lacewing, which is 14 mm (5/8 inch) long, gives off a disagreeable odour when threatened. Both adults and larvae prey on soft-bodied insects like aphids and mites.

The larvae hatch from white, stalked eggs laid on leaves. The brownish larvae have enormous curved pincers with which they seize their prey and suck it dry. Larvae are called "aphid lions" because of their ferocious appetite for aphids. They can consume a few hundred aphids in one day. After having reached about 6 mm (1/4 inch) in length, the larvae pupate in a white silk cocoon attached to the underside of a leaf. It takes 30 - 40 days for the eggs to develop into adults that live 4 - 6 weeks. One adult female can lay 100 - 200 eggs. The adult green lacewings appear at the beginning of the season and are important as early aphid control agents. Later the larvae take over most of that function. They will also attack mites, leafhoppers, small caterpillars, and thrips. Commercially raised green lacewings are available.


Green lacewing (photo courtesy of D. Gillespie)	Green lacewing larva

BROWN LACEWINGS (NEUROPTERA: HEMEROBIIDAE)

These gray-brownish lacewings are nocturnal like the green lacewings and are commonly found in and near wooded areas. Brown lacewing adults are smaller than green lacewings. The females deposit their eggs on foliage near a food source. The eggs are white, but turn orange or pink and finally brown just before the larvae are ready to hatch. Larvae are similar in shape and colour to the green lacewings. The head ends in shorter and stouter pincers which are used to hold on to the prey, pierce it and suck out the liquid body contents. The development from egg to adult takes 24 - 30 days and there are several generations per year. Brown lacewings are predaceous in their adult and larval stages and feed on spider mites, aphids and other soft-bodied insects.


Brown lacewing (photo courtesy of S. Marshall)	Brown lacewing larva (photo courtesy of S. Marshall)