NATURAL PEST CONTROL WITH GREEN LACEWINGS
Green lacewings is a general predator, as soon as the green lacewing eggs hatch the hungry larvae will eat aphids, mealybugs, scale, spider mites, thrips, whiteflies and other slow moving insects. To order Green lacewing eggs and get pricing and information, Please order Green lacewings for sale at Buglogical.com
THE “APHID LION” After a few days, the eggs hatch and tiny larvae emerge which are also known as” aphid lions” because of their voracious appetite. The larvae have sickle-shaped jaws (mandibles) with which they pierce prey and suck out body juices. Adults have chewing mouthparts. Adults are poor fliers, active at night and feed on pollen, nectar and honeydew (the exudate of aphids and other sucking insects). Some species are predaceous as adults to a limited extent. The larvae, called “aphid lions”, are extremely carnivorous and predaceous on many soft-bodied insects and mites, including insect eggs, thrips, mealybugs, immature whiteflies and small caterpillars. Larvae have sickle-shaped jaws that contain tubes with which they can inject prey with a paralyzing venom and then suck out the body fluids. They can consume over 200 aphids or other prey per week. There is no other better predator known to consume vast quantities of eggs and the soft bodies of aphids, mealy-bugs, spider mites, leafhopper nymphs, caterpillar eggs, scales, thrips, and white-flies. The lacewing larvae attack the eggs of most pests and, if the bodies are not to hard and fast moving, will attack the adult pest stage as well.
Use lacewing eggs, larvae for greenhouses and gardens. Larvae will only feed for 1-3 weeks before they become adults (eating only nectar and honeydew). Use approximately 10 lacewing eggs, larvae per plant or 1000 eggs per 200 square feet. After a few days, the eggs hatch and tiny larvae emerge. The larvae are gray-brown in color and newly hatch are very tiny. Similar in appearance to an alligator with pincers, the lacewing larvae vigorously attacks its prey, injects a paralyzing venom, and draws out the body fluids of its helpless victim. Depending on climate conditions, the adults will live for about four to six weeks, feeding only on nectar, pollen and honeydew. If these food sources are not avalable, it will simply leave the area and lay its eggs elsewhere.
Green lacewings are predators found in most environments. Several species of Chrysoperla and Chrysopa are important predators. The common green lacewing occurs throughout North America, while other species are more restricted in distribution. The light green adult has long, slender antennae, golden eyes, and large, veined, gauze-like wings that are 1/2 – 1/3 inches long. It is a slow-flying, nocturnal insect that feeds on nectar and pollen, and it emits a foul-smelling fluid from special glands if captured. The female lacewing lays eggs usually in groups on leaves, each egg held away from the leaf surface on the end of a slender stalk. A female lays up to 300 eggs over a period of 3-4 weeks, but often it does not survive that long in the field.
The larva, commonly called an aphid lion, resembles a green-gray alligator with mouthparts like ice tongs. An aphid lion seizes and punctures its prey with long, sickle-shaped jaws, injects paralyzing venom, and sucks out the body fluids. After feeding and growing to 1/2 inch in length during a 2-3 week period, the larva spins a spherical, white silken cocoon in which it pupates. The adult emerges in about 5 days through a round hole that it cuts in the top of the cocoon. It overwinters as a pupa within its cocoon or as an adult, depending on the species.
The green lacewing larvae are a voracious feeder and can consume up to 200 aphids or other prey per week. In addition to aphids, it will eat mites and a wide variety of soft-bodied insects, including insect eggs, thrips, mealybugs, immature whiteflies, and small caterpillars. Aphid lions will also consume each other if no other prey is available.
Green lacewings are available from Buglogical Control Systems generally offered as eggs. The released green lacewings larvae move around a lot and will travel 80-100 feet in search of prey. Once their food source is exhausted they will leave the area. The predatory larvae feed for 2-3 weeks before they become adults. The adults must have a source of nectar, pollen, or honeydew to feed on in the general vicinity of the pest area to stimulate egg laying, or they will leave. Providing an adequate food supply and suitable adult habitat can contribute to lacewings remaining and reproducing in the crop. Additional releases can provide a continuous supply of larvae if adults do not stay and reproduce.
The number of lacewings needed for effective control depends on the pest population and climatic conditions. For control of moderate aphid infestations in home gardens, 5-10 lacewing eggs per plant or 1,000 eggs per 200 square feet are recommended. General release recommendations for most crop situations start at 5,000 per acre for each application, but much higher rates may be necessary. Two or three successive releases made at two week intervals are better than a single release. Suppliers usually make recommendations based on specific situations. These insects are extremely effective under certain conditions, especially in protected or enclosed areas such as a greenhouse, but they may fail to survive and provide control when conditions are not favorable.
Because young larvae are susceptible to dessication, they may need a source of moisture. Adult lacewings need nectar or honeydew as food before egg laying and they also feed on pollen. Therefore, plantings should include flowering plants, and a low level of aphids should be tolerated. Artificial foods and honeydew substitutes are available commercially and have been used to enhance the number and activity of adult lacewings. These products may provide sufficient nutrients to promote egg laying, but they cannot counter the dispersal behavior of newly emerged adult lacewings.
Green lacewing eggs are shipped in bran or rice hulls and packed with moth eggs for food. The best time to release is early morning or later afternoon. Never release in the heat of the day. For best results, immediate use is advised however, when release is inconvenient, they can be stored in the refrigerator for up to 48 hours. Warmer temperatures will speed up their emergence and newly hatched lacewing larvae are hungry and will cannibalize each other if they are not released quickly.
If the infestation has not been arrested after 5 to 7 days, additional releases may be necessary. When releasing on a regular schedule, change the release sites within the target area to get maximum coverage.
Green Lacewing — Chrysoperla rufilabris
Green lacewing (scientifically known as Chrysoperla rufilabris) is widely used in various situations to control many different pests. Many species of adult lacewings do not kill pest insects, they actually subsist on foods such as nectar, pollen and honeydew. It’s their predacious offspring that get the job done. If you’re looking for effective aphid control, green lacewing larva should help do the trick.
The adult lacewing lays her eggs on foliage where each egg is attached to the top of a hair-like filament. After a few days the eggs hatch and a tiny predatory larva emerges ready to eat some aphid pests.
Lacewing larvae are tiny when emerging from the egg, but grow to 3/8 of an inch long. They’re known as aphid lions since they voraciously attack aphids by seizing them with large, sucking jaws and inject a paralyzing venom. The hollow jaws then draw out the body fluids of the pest, killing it. Of all available commercial predators, this lacewing is the most voracious and has the greatest versatility for aphid control in field crops, orchards, and greenhouses.
Each green lacewing larva will devour 200 or more pests or pest eggs a week during their two to three week developmental period. After this stage, the larvae pupate by spinning a cocoon with silken thread. Approximately five days later adult lacewings emerge to mate and repeat the life cycle. Depending on climatic conditions, the adult will live about four to six weeks.
Each adult female may deposit more than 200 eggs. For best results, habitats should encourage the adults to remain and reproduce in the release area. Nectar, pollen, and honeydew stimulate their reproductive process. If these food sources are not available, adults may disperse. An artificial diet called Wheast is available to provide the adults with the necessary nutrition they need for reproduction. Wheast powder mixed with sugar and water is used at Beneficial Insectary to help mass-rear the lacewing. Studies by universities and the USDA have shown that spraying field crops with a Wheast/sugar/water mixture increases egg laying considerably. Green lacewing adults can survive the winter in protected places but have a difficult time surviving cold winters.
As their common name implies, adult green lacewings are green, with four clear wings. Adult female lacewings live for approximately three or four weeks and lay up to 600 eggs. Each egg sits on the end of a slender stalk, which elevates it from the ground and decreases the chances of predation by ants. The eggs take approximately four days to hatch.
Larvae range in size from 1 mm at first emergence up to 8 mm just before they pupate. They have small spines on their backs upon which they impale the remains of prey. This provides a form of camouflage and allows the larvae to appear inconspicuous amongst the prey. Larvae pass through three moults over a period of 12 days before pupating inside a silken cocoon. Adults emerge after nine days and start laying eggs seven days after emergence.
- Aphids (various species)
- Twospotted mite Tetranychus urticae
- Greenhouse whitefly Trialeurodes vaporariorum
- Scales (various species)
- Mealybugs (various species)
- Moth eggs and small caterpillars
Larvae of the green lacewing are wide-ranging predators that will attack and eat almost any small insects or eggs. Lacewing larvae are particularly effective at controlling aphids and can consume 60 aphids in an hour. They will also attack mealybugs, greenhouse whitefly, thrips, twospotted mite, small caterpillars and moth eggs.
The green lacewing is one of the most common and widely distributed native lacewings in Australia. It is well suited to a wide variety of crops and habitats, including greenhouses, and is most active in warm climates. Lacewings are probably best suited to tree and shrub crops. Adult lacewings feed on nectar and pollen, so the presence of flowers after release will assist in keeping the lacewings within the crop. Cool temperatures slow down green lacewing activity and may induce diapause (hibernation).
Lacewings should be released before pests can reach damaging levels. As with other beneficial insects, it is better to release them earlier rather than later. Do not use residual pesticides within three weeks of release.
Lacewings are despatched as eggs and should hatch into the larval stage during transit. Eggs are packed with shredded paper to allow them a surface area, in lots of 100 or 500. The package includes a small quantity of sterilised moth eggs for food. Lacewings should be released when they reach the second stage of larval development. If the package is checked daily from arrival it should be quite easy to notice the sudden significant increase in size that indicates that the second stage has occurred. To ensure that the lacewings remain in the crop it is best if the shredded paper and containers with larval stages are distributed within the crop. The Lacewing larvae can also be sprinkled into our small release boxes and suspended on twigs or branches. This allows the larval stages ready access to the protection of foliage and to their food source. At this critical stage of release it may be necessary to control the ant population. Refer to the ant control blog.
Recommended release rates
- Field crops: Release rates vary considerably depending on the crop, the pest to be controlled and its density. A minimum of 2000-5000 lacewings per hectare should be released. Aim for 10,000 per hectare if possible.
- Nurseries: A minimum release rate of between one and five lacewing larvae per plant is recommended.
- Other situations: The number of lacewings needed for an individual situation can be determined after consultation with the suppliers. It is best to release larvae in pest hot spots, to ensure larvae have an immediate food supply.
It is preferable to make two or three releases 10 to 14 days apart to improve establishment of green lacewings in the field. Larvae take about 12 days to develop before they pupate in cocoons. After this time, there will be few lacewing larvae in the field, as it takes 16 days before adults emerge and lay eggs.
A note on release rates: Unlike chemicals which generally exhibit a clearly defined dose response curve, with beneficial insects, more is always better. However, they are costly to produce and the goal should be to achieve the best results at minimal cost. We are constantly trying to strike a balance between cost and efficacy. There are many factors that should be considered including the value of the crop, the magnitude of the pest population and the activity (or otherwise) of naturally occurring beneficial species. Also unlike chemicals, where it is common to respond to pest populations that have already exceeded some ‘economic threshold’, we recommend establishing beneficials early in the life of the crop before pest populations reach threatening levels. In most cases our releases are inoculative and we anticipate that our beneficials will establish and breed up within the crop to give long term control. As a general principle, 2-3 releases of modest numbers is better than a single large release – this reduces risk, improves establishment and accelerates the development of multiple overlapping generations of the beneficial species.
Since lacewing larvae camouflage themselves with dead prey items, some practice is needed to find them in the field. Normally they are more mobile than the pest, and can often be seen moving over plant leaves and stems. The lacewing cocoons are usually well hidden and difficult to find. Adults fly at night and are attracted to lights, so avoid leaving lights on at night.
Lacewing eggs can readily be seen on their distinctive long slender stalks. Start scouting for eggs approximately 30 days after releasing larvae.
Cultural practices to aid establishment
Adult lacewings will persist in the crop if nectar and pollen are present. Practices such as strip intercropping and encouraging flowering plants will give best results.
Little is known about insecticide toxicities to lacewings. It is reasonable to assume that unless the pesticide is specific to one particular group, for example a miticide, it will have some sort of harmful effect on lacewings.
Lacewings are despatched by express post or overnight courier and should be received within 48 hours. Lacewing should not be released until the eggs have hatched and developed into the second stage larvae (see above). If necessary they can be stored as eggs or young larve for several days in a cool, dark place. If storage is required, containers should be turned upside-down daily to allow re-distribution of their included food supply. If lacewings are held for too long such that their food supply becomes depleted they may start to cannibalise each other.
Now available our new garden pack consisting of 300 lacewing eggs, 6 release boxes and 2 yellow sticky traps. Great for the home garden or vegetable plot on the balcony.