Beneficial garden animals: 10 useful insects and critters for your garden
It is almost always unnecessary to use chemicals in your garden, as there are plenty of beneficial garden animals that can get the job done for you. Discover our top 10 beneficial garden animals, including lots of beneficial insects, and find out how to draw them to your garden.
When slugs (Gastropoda) raid our vegetable patches and aphids (Aphidoidea) get out of hand, many gardeners feel compelled to resort to pesticides. However, there are much more sustainable ways of controlling these unwanted guests, including accepting the help of beneficial garden animals and insects. These little helpers can help out more than you might think. They can drive pests away, ensure a larger harvest or improve the structure of your soil. Read on to find out which beneficial garden animals and insects there are and how to encourage them to settle in your garden.
The European hedgehog (Erinaceus europaeus) is an insectivore, primarily feeding on beetles, caterpillars, earwigs and millipedes as well as earthworms and snails. Less frequently, it will reach for fallen fruit and berries if there are not enough insects about. However, the assumption that this beneficial garden animal will keep your garden free of snails is not entirely correct, as these only make up a small part of a hedgehog’s diet. Moreover, slugs, just like earthworms, can transmit harmful parasites to hedgehogs. Our prickly friends need a large territory to find enough food, so it is important to make your garden accessible to them. Hedgehogs prefer to live in natural gardens, which have piles of leaves, hedges and piles of wood and offer them plenty of places to hibernate. See our article on how to support hedgehogs in autumn to find out how you can help. But there is also a downside to having these hungry, nocturnal little helpers in your garden – besides pests, they also like to eat some beneficial insects, such as earthworms, or the eggs of ground nesting birds.
With their bright red bodies and black spots, ladybirds (Coccinellidae) are not only useful, but also beautiful. An adult seven-spotted ladybird can eat up to 150 aphids a day and its larvae are insatiable. Ladybirds also eat spider mites, scale insects (Coccoidea), firebugs (Pyrrhocoris apterus), fringe winged beetles, and various beetle and sawfly larvae. If ladybirds run out of insects, they simply switch to pollen and fruit. Some species even chow down on powdery mildew (Erysiphaceae), a harmful fungus. These colourful beneficial insects feel particularly at home in hiding places under foliage, in piles of stones and under clumps of plants and grass.
3. Ground beetles
Admittedly, ground beetles (Carabidae) are not the most beautiful beneficial insects of all and most people tend to avoid them because they emit a smelly secretion when in danger. As ground beetles are nocturnal, we do not see them very often anyway. Nevertheless, these up to four centimetre long dark beetles with sturdy little legs can consume three times their body weight in food per day, so are great to have in your garden. Due to their predatory lifestyle, their diet consists mainly of the eggs and larvae of growing insects, worms and snails. They also eat aphids (Aphidina), potato beetles (Leptinotarsa decemlineata), caterpillars, wireworms (Elateridae) and various mites. Ground beetles feel particularly at home under leaves and brushwood, under piles of stones or in well-hidden, shady, damp places. The best-known representative of this group is the golden ground beetle (Carabus auratus), whose shiny green-gold carapace is quite impressive.
4. Ichneumon wasps
Ichneumon wasps (Ichneumonidae) are tiny parasitic beneficial wasps measuring only 0.4 mm in size, and are a real insider’s tip when it comes to natural pest control. The female ichneumon wasps lay her eggs in the body of the host with the help of a sting, and the larvae then develop there. After the new generation hatches, only the empty, eaten shell of the pest remains. Some species of ichneumon wasps can also be used against leaf-miner flies (Agromyzidae), the larvae of aphids or the eggs of the European corn borer (Ostrinia nubilalis) and codling moth (Cydia pomonella).
To encourage ichneumon wasps in the garden in a natural way, leave some dead wood lying around to serve as a hiding place for these beneficial insects. Ichneumon wasp females also use long grasses as hiding places and winter quarters. Planting a rich variety of flowers is not only a beautiful sight for us, but also provides sufficient food in the form of nectar for these parasitic wasps. These small beneficial insects prefer umbellifers which are plants from the Apiaceae family, such as common yarrow (Achillea millefolium).
Not all beneficial organisms help by directly controlling pests. Some quietly ensure that the plants in our garden grow and thrive by improving the soil, the best example of this being the earthworm (Lumbricidae). Earthworms loosen the soil structure through their tunnels, provide better aeration and water infiltration, work residual plant matter into the soil and excrete valuable worm humus, which is a great, natural plant fertiliser. These beneficial worms feel most at home under a layer of mulch. So, to promote the earthworm population in your garden, mulch regularly and gently till the soil now and then.
6. Gamasina mites
Gamasina mites (Gamasina) are beneficial insects that are only about 0.6 mm in size, but are very effective at controlling a variety of pests. They use their special mouth tools, the chelicerae, to injure their prey and then suck them dry. Various species of the genus Amblyseius are good against thrips (Thysanoptera) and are also commonly used in greenhouses. In contrast, Hypoaspis aculeifer and Hypoaspis miles are good against mosquito species that lay their eggs in the soil, such as the fungus gnat (Sciaridae). Spider mites (Tetranychidae) and red mites (Panonychus ulmi) are best controlled with Phytoseiulus persimilis. Just one of these small beneficial insects eats up to 20 eggs or nymphs in one day. This type of biological pest control is very effective, as just one predatory mite per leaf is enough to keep the spider mite population down. To do this, carefully place the beneficial predatory mites in the inner part plant and leave them to it. As beneficial insects are creatures with specific needs, you must pay attention to temperature, light and humidity so that they can do their job well. You can find an informative overview of beneficial insects against pests in our separate article.
7. Green lacewing
Green lacewings (Chrysoperla carnea) look rather inconspicuous, but having them in your garden is great as each larva of this beneficial insect can eat up to 50 aphids (Aphidina) per day. They also eat thrips, spider mites and other small insects. Green lacewings work similarly to predatory mites. They sting their prey with their mouth parts and suck them dry. Green lacewings have very fine, iridescent wings, which are often roof-shaped over the hind body. A female lacewing can lay up to 900 eggs at once, and she lays them near aphid populations to ensure that her offspring have enough to eat.
Birds are some of the most popular visitors in many gardens, and not surprisingly considering they are some of the most interesting and beautiful animals around. But our feathered friends are not only beautiful to watch, but are often also excellent beneficial garden animals. Blue tits (Parus caeruleus) in particular do a unique job in the garden, feeding up to 1.5 kg of insects to their offspring to raise one brood. In addition to winter moth caterpillars (Operophtera brumata), ermine moths (Yponomeutidae), codling moths (Cydia pomonella) and spotted wing drosophila (Drosophila suzukii), blue tits also like to eat the caterpillars of the dreaded oak processionary moth (Thaumetopoea processionea). To make blue tits feel more at home in your garden, it may be worthwhile hanging up birdhouses and maintaining natural nesting cavities. Flower meadows and fruit trees also provide a valuable food source as well as sufficient protection against predators for these birds. To help the birds in your garden get through the winter months, make sure that there are enough fruits and seeds for them to eat. Setting up a feeding place for birds is also a good idea.
Tip: To ensure that the nest boxes are indeed suitable for blue tits, the entrance hole needs to be about 26 mm in diameter.
When gardeners think of nematodes, they think primarily of vegetable pests. But not all nematodes feed on fresh veg. The nematodes of the species Steinernema carpocapsae, for instance, are beneficial insects that love to eat bothersome pests. Mole crickets (Gryllotalpa gryllotalpa), but also the larvae of the crane fly (Tipula paludosa) and earthworms, no longer stand a chance when nematodes are about. The genus Heterorhabditis, on the other hand, can be used effectively against vine weevils (Otiorhynchus), slugs, and garden chafer grubs (Phyllopertha horticola). Find out more about nematodes as beneficial insects in our in-depth article.
10. Bees and bumblebees
Last but not least, bees and bumblebees. When you think of beneficial insects in the garden, these little helpers are probably the first that come to mind. This is not surprising considering the positive impact they have on our garden. Through their industrious work as pollinators, these insects are essential to a good harvest, especially when you consider that nearly 80 percent of crops rely on pollination by insects such as bumblebees, bees, butterflies and wild bees. Honey bees are popular pollinators because of their sweet honey, but wild bees such as the bumblebee are also irreplaceable pollinators. The latter can pollinate many plants, for example the tomato (Solanum lycopersicum), much more effectively than the honey bee could, thanks to their long proboscis and a very special vibration technique. To make the garden attractive for bees and bumblebees, it is important to ensure there is a permanent food supply from spring to autumn. These pollinators prefer a diverse selection of native flowering plants. An insect hotel can also provide additional breeding space.
Establish beneficial insects in the garden
Beneficial insects in the garden make work easier for gardeners and are a good way of practising sustainable and biological plant protection. However, this raises the question of how to get beneficial insects to settle in your garden in the first place. In fact, it does not take much for insects and co. to feel at home in your garden and start doing their work. Above all, gardeners should take care not to use chemical insecticides or similar products, as these not only kill the pests, but can also be harmful to helpful beneficial insects.
Generally speaking, it is best to keep things as natural as possible when designing an insect-friendly garden. Native plants usually offer pollinators a much better yield than exotic rarities, wildflowers offer more hiding places than an English lawn, and hedges and shrubs attract beneficial insects more successfully than a painted garden fence. Those who do not place quite so much value on strict tidiness have even better chances, because dead wood, piles of leaves and cuttings are ideal habitats for beneficial organisms. If you do not have the possibility to design your garden in a natural way, you can resort to a so-called insect hotel. This self-made or purchased shelter for beneficial insects not only looks decorative, but also offers the animals a suitable shelter.
A simple way to establish insect-friendly plants in the garden is to sow an insect pasture that provides food and habitat for a wide variety of beneficial garden animals, including garden birds, ladybirds, bees and butterflies and numerous other beneficial insects.
Purchasing beneficial insects for the garden
Beneficial insects are usually bought for use indoors or in greenhouses. This is because in the garden they quickly become interested in the neighbouring plants, even if there is less food there. They tend to migrate or get eaten by other insects or birds, stopping them from controlling the pests you intended them to tackle. Hence, it is better to buy beneficial insects for indoor use.
It is also better to encourage the natural population of beneficial insects by allowing a small number of pests to stick around in your garden. Many pests provide the perfect basis for the development of a large population of beneficial insects, allowing any future pest problem to quickly regulate itself.
You cannot rely on natural populations of beneficial insects to keep pests off your houseplants or out of your greenhouse, as the warm, windless conditions quickly lead to gigantic pest populations. For these cases, buying beneficial insects is your best bet, not least because they are non-toxic to you as the user and do not harm your pets or plants.