My introduction to the lovely green lacewing was when we were growing a demonstration garden at our fairgrounds. Our sweet peas were suddenly inundated with aphids. We did not want to spray them, so we did a wait and see. In two days I saw the first lacewings, lady beetles (aka ladybugs) and even yellow jackets at work. Later in the season the larvae of the lacewings and lady beetles arrived. We never had to spray and the sweet peas survived, thrived and rewarded us with sprays of sweet scented flowers.
There are a number of lacewings in different genera and species. The Spotted Giant Lacewing and the Brown Lacewing are found primarily in the western US and Canada. There are 16 species of the Green Lacewings, which include the one described below. It is the one most often found in our gardens and croplands.
Lacewings belong to the Order Neuroptera, which means netted wings. Their large, fragile looking wings have a fine net pattern. Lacewings are one of our finest beneficial predators. The Golden Eyed Green Lacewing adults are light green with threadlike antennae and golden eyes. They are about an inch in length. The adults feed only on nectar, pollen and “honeydew”, a secretion from aphids. Lacewings are poor fliers and usually are out at night. Sometimes they are attracted to house lights. They are marked by their longevity (adult green lacewings live 2.5-3 months), high fecundity and fast developmental rates. Adults are attracted by the odor of aphid honeydew and lay their eggs near aphid colonies. They are found all across North America.
Their fierce looking larvae are hungrier than the average teenager. The larvae are quick, flattened brown and white with jaws that look like ice tongs. The “tongs” are hollow, allowing a digestive secretion to be injected in the prey. An aphid can be dissolved by this in 90 seconds.The larvae seek their prey by weaving their head from side to side until contact is made. A nickname for them is aphid lions. A lacewing larva grasps the aphid with its grooved, caliper-shaped jaws, often lifts it up in the air, then drinks the fluids in the aphid’s body. A single lacewing larva can eat an aphid a minute, for hours, and not slow down. The larvae are not very finicky eaters as they will also eat other larvae and insect eggs. They also find lace bugs, cabbage worms, corn earworms, mealybugs, some scales, spider mites and whiteflies quite tasty. In fact, they are so predatory that the females lay the eggs on the ends of long, upright threads so the new hatchlings won’t consume the late comers.
Green lacewings can be purchased as adults, eggs or larvae. Usually the adults are not practical as they are easily damaged. If you do buy eggs or larvae, be sure to spread them out in the garden right away, because otherwise you may lose most of your purchase to cannibalism. Eggs are the easiest to handle. The larvae may bite.
Since the adults need a food source, be sure to have some of the good pollen plants in your garden such as any members of the carrot family which flower, the daisy family, tansy and especially dandelions. Remove row covers from plants during the evening hours so lacewings can check them for pests. Avoid all pesticides when you see lacewings. Should you notice an aphid problem that needs to be brought to the attention of lacewings, spray plants with a light solution of sugar and water (1 tablespoon sugar per cup of water). The sugar water simulates aphid honeydew, and can quickly increase visits by lacewings and lady beetles.