The graceful lacewings are the elves among insects. The pretty tiny creatures feed primarily on honeydew and flower nectar. Large predators, on the other hand, are the lacewing larvae, because a single larva eats between 200 and 500 aphids and other plant pests before pupating.
What are lacewing larvae used for?
Lacewing larvae are beneficial insects that feed on aphids and other pests. They can be used in the garden or indoors to control pests naturally. Lacewing larvae are available from specialist retailers and can be spread directly onto infected plants.
Use lacewing larvae against aphids
Aphids are one of the biggest nuisances of every gardener, as they quickly develop into a gigantic pest due to their asexual reproduction method: colonies of thousands of animals suck the juice out of roses and other garden plants and thus cause considerable damage to the plants.
Prevention is the magic word here, so that such problematic populations cannot develop in the first place. A garden close to nature creates the best conditions for aphid-eating beneficial insects to settle there. The larvae of the lacewing (Chrysoperla carnea) are considered particularly voracious in this regard, as they prefer to eat aphids until they pupate. For this reason, the lacewing is often referred to as the “aphid lion”. Another name for the slender insects with the transparent, shimmering green net wings and the gold-colored eyes is “Goldeye”.
The netwings - contrary to what their name suggests, lacewings are not flies - lay their eggs, which are attached to long stalks, directly on the leaves of garden plants from May onwards. As a rule, the females look for a place in the immediate vicinity of an aphid colony to lay their eggs so that the larvae do not starve. The elongated, brownish-colored larvae have six legs and are quite agile. However, they do not eat the aphids completely, but grab them with their pincer-shaped jaws and suck them out. All that remains are the empty quinine casings.
Lacewing larvae feed on aphids
Application
If you have an aphid problem in your garden or greenhouse, you can buy the aphid lions to combat them from specialist retailers and apply them directly to the affected plants. The larvae are available in two variants:
- Scatterware: These are the eggs of the lacewing or the tiny larvae in the first instar. Gently turn the can (do not shake!) so that the contents mix well. Now scatter the eggs and larvae directly onto the plant leaves. Leave the container at the base of the plant for a few more days so that stragglers can still make their way
- Cardboard honeycomb: Larvae of the second instar are packed in cardboard honeycombs, where each larva has its own honeycomb. This is necessary so that the cannibalistic animals do not eat each other.
Apply cardboard honeycomb as follows:
- Open the packaging and take out the cardboard honeycomb.
- Hold the honeycomb horizontally and carefully peel off the gauze taped over the opening.
- Prepare a slightly damp paper towel.
- Carefully tap the larvae in the honeycombs onto the kitchen paper.
- Now place the cloth on the affected plant or hang it inside.
- Now the larvae can overflow and go looking for food.
- Leave the cardboard honeycomb under the plant for a few more days so that stragglers can still overflow.
You should also make sure that there are no ants on the plants. The aphids like to keep them as “pets” and actually protect the pests. To prevent the ants from carrying away and eating the lacewing larvae, you should water your plants thoroughly before planting them. Be patient after application: it takes about a week to ten days to see results.
The advantage of lacewing larvae compared to other beneficial insects lies not only in their large appetite, but also in their high activity even at temperatures of 12 °C. If necessary, repeat the application after 14 days.
Tip
You should release around 150 larvae per ten square meters of area. Be careful not to release too many larvae. These then eat each other and leave the aphids behind.
Use lacewing larvae in the apartment
lacewings can also be used indoors for pest control
The lacewing larvae are also very suitable for use indoors, for example on houseplants plagued by aphids or other pests or in the greenhouse. The application is the same as described above, but the pupated, adult lacewings must finally be released outside. They could not survive in the apartment or greenhouse because they usually cannot find suitable food there or it can get too warm for them. In any case, the adult animals often find their way outside on their own. So every time you have an infestation you have to buy new larvae and release them.
Background
Lacewing larvae have a wide range of prey
Although aphids are the absolute favorite food of lacewing larvae, the animals also eat other pests such as spider mites, thrips, scale insects and mealybugs and their eggs. A single larva can suck out up to 12,000 spider mite eggs, significantly reducing the infestation pressure.
Attracting lacewings – This is how you bring the beneficial insects into your garden
So that you don't have to constantly buy the useful lacewings, you should make it easier for them to settle in your garden. For this purpose, the garden should be cultivated as close to nature as possible and contain many flowering plants. Incidentally, catnip is said to be particularly attractive to lacewings, as the scent of this pretty purple flowering plant is very similar to the sexual attractant of lacewings. Purple coneflower (Echinacea purpurea) and other nectar-rich flowering plants that bloom in late summer are also suitable. These include:
- Nasturtium
- Marigolds
- Tagetes
- Borage
- Zinnias
- Sedum
- Summer Heath
- Sun Bride
- Sunflower
- Astilbene
- Phlox
The plants mentioned not only attract lacewings, but also other useful insects such as bees and bumblebees. However, be sure to only plant varieties with single flowers, as double flower heads are worthless to insects. These look pretty, but produce little or no nectar.
In winter, lacewings need a suitable place to overwinter. The animals like to nest in cool rooms such as the garage or a garden shed. So-called lacewing boxes are also popular. You can buy a lacewing box (€25.00 on Amazon) from specialist retailers or simply build it yourself. This article explains how this works in a clear and entertaining way:
Florfliegenkasten ganz einfach selber bauen
The red color is not because it looks prettier, but because red is very attractive to lacewings. By painting it you increase the chance that the beneficial insects will settle in this box. By the way: Contrary to what is stated in the video, the insects do not use the box for nesting (after all, they lay their eggs directly on the plants). Instead, they overwinter in it and then start right there the following year. So aphids etc. have no chance right from the start!
Hands off pesticides
“Pest control works better with beneficial insects such as lacewing larvae than with toxic chemicals.”
If you want to successfully control the pests with lacewings and other beneficial insects, you must definitely avoid using any pesticides. Insecticides and fungicides not only kill unwanted pests, but also kill beneficial insects. The same applies to oil-based products, for example those based on neem or rapeseed oil. Both are often used in organic gardening, but often have the same effect on beneficial insects as they do on pests. Avoid applying such products for at least six weeks before planning to use beneficial insect larvae, otherwise you will kill the animals and they will of course no longer be able to do their job.
Excursus
Which beneficial insects can you use against aphids?
Other beneficial insects can also be used very well against aphids. Ladybugs and their larvae, for example, have a great appetite because they eat between 400 and 800 aphids per animal within their approximately 20-day lifespan. After hibernation, ladybugs are particularly hungry and therefore do a lot of cleaning up in the garden in spring. In addition, parasitic wasps, hoverflies and predatory bugs are also suitable for natural pest control. You can release the beneficial insects together with the lacewing larvae, but you should then make sure that the different animals do not get in each other's way.
Frequently asked questions
Do lacewing larvae also bite people?
In fact, lacewing larvae can bite forcefully with their pincers, which is why it is better not to pick up the animals or touch them in any other way. Your bite can be very painful and also shows symptoms similar to those of a mosquito or wasp bite: the bite site becomes red, possibly swollen and itches. However, such a bite is not dangerous.
Can I still release lacewing larvae in autumn?
In principle, due to their short life cycle, it is still possible to release lacewing larvae even in autumn, as long as the temperatures are consistently above 12 °C (even at night!). If it is too cold, the animals slow down their metabolism and no longer eat as much. It would therefore make more sense to make the garden or greenhouse winter-proof and to dispose of the plant parts affected by aphids with household waste. This way you will keep the plague at bay the following year. In a warm room, however, you can use the animals at any time, but the adult animals will then die. They do not overwinter in warm rooms and it is often too cold outside from October onwards.
How long do lacewing larvae live?
Lacewings have a very short life: The larval period occurs in three phases (only from the second phase onwards do the animals eat aphids and other pests!) and lasts around 18 days. The animals then pupate and live for another two to three weeks. Two to three generations of lacewings are raised per season.
Tip
If you have children, you can buy and release lacewing eggs along with them. The little ones then see up close how larvae hatch and develop into a lacewing. Real-life biology lessons for at home!
