In past articles I’ve written about some of the evil garden culprits that reside in the insect world. And when we think of the good guys (aka beneficial insects) in our gardens most of us usually think only of those cute little red and black ladybugs. So, when I recently went out the other day to visit my lovely clematis, I was happy to find a tiny green lacewing resting on my pretty Clematis ‘Durandii’ (http://.www.clematisqueen.com/content/martha-stewart-favorite). I am always excited to see lacewings due to the fact that they are not fickle friends like the ladybugs because they are not as prone to fly away to your neighbor’s garden on the first gust of wind. In my opinion, the green lacewing is a far superior knight in shining armor in our gardens.
Life Cycle of Green Lacewings
The life cycle of lacewings is heavily influenced by temperature and climate. They can have two to four generations per year depending on climatic conditions. Usually the life cycle is 40 days, but in warm, humid summer conditions, with a long day length, they may complete their life cycle in just 30 days. In warmer locals the adult lacewings can overwinter in leaf debris throughout your garden. In colder areas the lacewing pupae overwinter and then the adults emerge in late March and early April.
Adult Lacewings
It is easy to recognize adult green lacewings (scientifically known as Chrysoperla rufilabris) by their delicate and transparent wings, which are pastel green with a black venation. Its slender body is between ½ to ¾ of an inch long. The reason you may have not spotted them in your garden is because they are nocturnal. When seen in the day they are easy to identify because they are weak fliers that can only flutter slowly for short distances. If threatened, they emit a foul smelling fluid from special glands which I imagine makes it not very attractive to birds, etc.
The delicate adults do not devour the pest insects in your garden. It is their predacious offspring who eliminate those unwanted culprits. Adult lacewings subside on nectar, pollen and honeydew. One of their favorite foods is the aphid’s honeydew and this is also where the female often lays her eggs because it will offer the larva prey after they have hatched. Depending on climatic conditions, the adult will live about four to six weeks.
Eggs
During the spring and summer the females lay several hundred tiny eggs on the underside of leaves, bark or twigs on trees in the vicinity of prey. Each egg is attached to the top of a silken stalk. She lays them singly on a hair-like filament which projects ¼ to ½ inches above the surface of leaves or stems to which they are attached. The lacewing larvae then emerge in 3-6 days ready to eat the pests.
Lacewing Larvae
For all intents and purposes it is the larvae that do battle with the evil insects. In their larval stage they look nothing like their delicate parents, resembling tiny alligators with fierce-looking mouth parts. They will grow to 3/8 of an inch in length. They are very active and mobile on plants and will travel 80-100 feet in search of prey. With their nasty, sickle-shaped jaws they seize their prey, and then inject them with paralyzing venom. These jaws are hollow, enabling them to suck out their prey’s bodily fluids. A rather horrid depiction, but I couldn’t think of a better way that the nasty likes of aphids, whiteflies, leafminers, spider mites, mealybugs, leafhopper nymphs and the eggs and caterpillars of most pest moths should meet their fitting demise. The larvae have earned the nickname ‘aphid lion’ because of their enormous appetite for aphids.
The predatory larvae feed for 2-3 weeks before becoming pupae. The good news is during this time a single lacewing larva can consume as many as 1,200 of the above pests. So, when you see these gruesome little creatures don’t mistakenly try to destroy them because they are the good guys!
Lacewing Pupae (Cocoon)
Once the larva is mature, it will spin from a thread that resembles silk a small, round, parchment-like cocoon (pupa) on the underside of leaves. In approximately 5 to 7 days an adult lacewing emerges from the cocoon to start the life cycle all over again.
Purchasing Lacewing Eggs
Green lacewings are available for sale from commercial sources. Lacewing eggs can be purchased for release in the garden to boost the existing populations and/or to provide extra protection.
Releasing lacewings into your garden is simple and cost effective. The general rate of release is 5 to 10 lacewing eggs per plant or 1,000 eggs per 200 square feet. Two or three successive releases made at two-week intervals are better than a single release.
Lacewing eggs are shipped in several different forms such as: in vials, on tape or on cards. For the freshest eggs select a beneficial insect company that will ship the eggs directly to your home. Eggs have a very short shelf life, so it is important to place them in your garden as soon as possible after receiving them. The best time to release is early morning or late afternoon. Never release in the heat of the day.
Important Note: Remember not to release them near ants because the ants will eat the eggs.
How To Provide A Lacewing Habitat
Providing an appropriate habitat for adults will encourage existing and/or released lacewings to stay in your garden, otherwise you will need to make additional releases to maintain a continuous supply of larvae.
Here are some guidelines:
Introduce plants that will provide pollen and nectar as food sources to keep adult lacewings in your garden.
Tolerate a low level of aphids (https://www.clematisqueen.com/content/spring-aphids) because they provide a source of honeydew for adult lacewings.
To encourage beneficial insects in your garden, be sure to refrain from using pesticides of any kind (including dusts). Pesticides are not picky; they kill all the insects in your garden…even the good ones.
Leave some leaf residue in the garden and reduce tillage to provide more stable surroundings.
Provide water both above and on the ground so the larvae will not become dehydrated.
Eliminate ants by applying a sticky barrier around the base of your trees and shrubs because they eat lacewing eggs and attack larvae.
Predators such as lacewing larvae are good for the garden. These larvae are beneficial, natural enemies that attack aphids and other potential pests, reducing the size of their population and subsequently the amount of plant damage that occurs. This, in turn, can reduce your need to use insecticides.
Lure beneficial insects to your garden with good supplies of their favorite foods. Small flowered plants, such as members of the mint family, are favorites with insects. Any small flowered plant will attract insects with its pollen.
With the right plants it is easy to convince a colony of Lacewings to call a healthy garden their home.