the essentials in brief
- There are around 27,000 scarab beetle species worldwide
- the Grubs scarab beetles nibble on the roots of plants, while the adult beetles feast on the leaves
- Scarab beetles are best controlled by nematodes or with the help of predators
- It is even better to prevent an infestation with regular chopping, root protection mats or insect nets
This is how you can spot a scarab beetle in good time
White grubs do not eat plant roots for years, but feed on them first humus. Only from the second year onwards do the larvae attach themselves to the fine roots (and, depending on the species, also to others Plant residues) in order to then dig up to 60 centimeters deep into the ground and close pupate. They remain in this state for another one to two years. While the adult beetles can be spotted quite quickly - and eggs are likely to lay - the grubs are often only discovered by chance.
also read
- Should you fight rose chafer grubs?
- Use nematodes against grubs
- Leaf bug: types, characteristics and means of control
The plants on the infested areas seem to die without any cause. If you can rule out other reasons, the grub infestation can be substantiated quite well with a test excavation on the affected area: The yellowish-white larvae are in the excavation. By the way, you don't have to dig particularly deep, because the animals are only a few centimeters below the surface of the earth.
While the beetles “only” cause damage above ground, the larvae quietly and secretly eat the roots
Prevention is better than fighting
You can prevent an infestation with scarab beetles and their larvae with a few specific measures. However, these methods are not one hundred percent secure. The most important thing is not to leave the lights on during the main flight time of the different species in the garden: The mostly nocturnal or crepuscular animals feel attracted to it and prefer to lay their eggs near the light sources away. Other useful prevention options are:
- Mosquito nets: mainly on compost and manure heaps as well as on open ground
- Root protection grid: protect the rhizomes of plants from the larvae
- Lawn edging: Surround the beds with deep curb stones, the grubs cannot get through here
- Ground work: hoeing, raking, pulling weeds and regular digging of the soil in spring or autumn disturbs and damages the grubs
Tips
To protect lawns from death caused by grubs, consider the Sward scarify regularly. If that doesn't help either, you should remove the dead lawn, dig up the area deeply and sow again.
Fight scarab beetles effectively
“Collect the cockchafer and rip off their legs and wings. Then toast them in hot butter until crispy. Then cook them in chicken soup. "(Centuries-old recipe for cockchafer soup)
If the damage is already visible, the plants that have been eaten by grubs cannot be helped. Since the larvae eat the underground roots, the above-ground parts of the plant can no longer be supplied and dry up. In addition, cockchafer larvae occur in abundance - wherever you find a maggot, there are certainly many others in the ground. No wonder, then, that the previous numerous populations were collected and processed into a nutritious cockchafer soup - perhaps your grandparents still know this.
The following options are available in the garden for effective control.
Collecting
In earlier times, one of the main occupations of children during the summer months was collecting cockchafer and their larvae. Even today, the method is effective for the hobby garden, even if it is laborious and time-consuming. The easiest way to collect the grubs is after a heavy downpour, because then the animals come to the surface and can be easily picked up. Such rain can be artificially imitated by vigorously watering the infested areas.
Alternatively, you can simply dig up the soil interspersed with white grubs and thereby bring the larvae to light. This method also has the advantage that the soil is loosened and weeds are removed.
Fight biologically with nematodes
Nematodes are available in stores specifically against the larvae of May or June beetles, which reliably kill the pests. These are microscopic nematodes that are in a Clay granules to be delivered. Simply mix the granules with the irrigation water and water the affected areas in the garden extensively. The roundworms become active in the soil, penetrate the grubs and kill them.
Natural enemies
Birds are the best protection against scarab beetle pests
One of the best ways to get rid of pesky grubs is to make the garden inviting to hedgehogs, moles, bats, and birds. The fat maggots and the adult beetles like to eat them and thus keep the population low in a completely natural way. Mice, martens and large ground beetles also like to eat grubs. So that the beneficial insects feel comfortable, install
- appropriate roosts (bird houses, bat boxes, brushwood piles)
- Watering stations and feeding stations with a few delicacies (birds feed in winter!)
- Planting forage and protection plants, for example dense hedges
If you are also the happy owner of a flock of chickens, you can let them run over fallow beds in spring and autumn and across meadows and lawns all year round. The animals specifically peck the grubs out of the ground.
Insecticides against scarab beetles?
Some pesticides are approved for the home and hobby garden as well as for the lawn, which reliably remove the grubs. These include, for example, products made from the seeds of the neem tree native to India, the toxic ingredients of which hinder the larvae in their development. However, you should not use insecticides if possible, because these - regardless of whether they are chemical or natural Agents such as neem oil are involved - always have serious effects on the entire ecosystem in the garden and thus also useful animals to have.
Just because a product bears the label “natural” does not mean that it is safe. After all, nature itself produces the most harmful poisons and is therefore anything but “gentle”.
What are scarab beetles?
The scarab beetle (lat. Scarabaeidae) are a very large and complex family within the order of the beetles (lat. Coleoptera). About 27,000 different kinds in about 1600 genera belong to the worldwide occurring beetle family, which externally look quite different and range in length from a tiny two millimeters to a strikingly large 16 centimeters can. Not all species pose a problem in the hobby garden, some - such as the rhinoceros beetle, which is threatened with extinction and therefore under nature protection - are also considered beneficial insects.
species
Typical species of scarab beetles that are relevant for the garden are the following:
- June beetle: also ribbed curl beetle, lat. Amphimallon solstitiale
- Common cockchafer: also field cockchafer, lat. Melolontha melolontha
- Shiny gold rose beetles: also common rose beetle, lat. Cetonia aurata
- Rhinoceros beetle: lat. Oryctes nasicornis, feeds on dead wood and is therefore often found in bark mulch
- Garden beetle: lat. Phyllopertha horticola, are often confused with the June beetle, but cause little damage
For many centuries, the cockchafer in particular was notorious as a pest and could come back every year due to the immense feeding activity of its grubs, considerable damage - and thus also famine - trigger. Nowadays the cockchafer is through drastic measures mainly in the 1950s and 1960s has become rather rare, but still causes great damage in warm years and in certain regions at. The following video shows the newly emerged problem quite impressively:
Youtube
Typical appearance of scarab beetles
The scarab beetles mentioned above look very similar, so that mix-ups cannot be ruled out. However, an exact determination of the species occurring in the garden is important, otherwise the control measures can run into the void - not every Käferengerling reacts as desired to the initiated Elimination methods. For this reason you will find some relevant clues for the exact identification of the species in the following table:
| Cockchafer | June beetle | Shiny gold rose beetle | Garden beetle | Rhinoceros beetle | |
|---|---|---|---|---|---|
| Occurrence | almost all of Europe, rare in the Mediterranean | Northern and Central Europe outside the mountains | Europe and Asia, v. a. Central and Northern Europe | all of Europe and Asia | Europe, Asia, Africa |
| habitat | open landscapes with few trees | Fields, gardens, forest edges, parks | Hedges, gardens, forest edges, parks | in meadows, fields, on the edges of forests, in gardens and hedges | especially in forests, also in tree-lined gardens and parks, compost heaps |
| frequency | now more often again | locally dependent, often to rarely | locally dependent, often to rarely | widespread | Rare |
| Nutrition of the adult beetle | Leaves of deciduous trees | Leaves and flowers | often in flowers (pollen, nectar, sap) | Birch, hazel and oak leaves, rose and cherry blossoms | Vegetable juices (e.g. B. of tree leaves) |
| Nutrition of the grubs | Plant roots, plant residues | Dead wood, often in bark mulch and compost | Plant roots, especially in the lawn | Dead wood, often in bark mulch and compost | |
| Deck wing | red-brown, can be lighter or darker | three raised longitudinal ribs, dotted between them | two broad longitudinal ribs, white transverse grooves and spots | light brown, six dotted vertical stripes on each wing | smooth and shiny, with fine rows of dots |
| coloring | black except for legs, elytra, and antennae | dark yellow to brown | green to bronze-colored, shiny metallic, red-gold underside | except for the wing-coverts black-green, shiny metallic | dark red-brown to black, very shiny |
| size | two to three centimeters | 14 to 18 millimeters | 14 to 20 millimeters | 8 to 11 millimeters | 2.5 to 4 centimeters |
| Special marks | End of abdomen not covered by wings | light midline between pronotum and elytra | different colors possible, but always with a metallic sheen | thick hair all over the body | The eponymous "horn" is only worn by the males |
| Flight time | from the beginning of May to the beginning of June | from the beginning of June | April to October | End of May to end of June | May to June |
| Larval activity | from July | from mid to late July | from June | July to October | from June |
| White grubs appearance | three pairs of legs, yellowish-white, brown head capsule, curved | yellowish-white, brown head capsule, curved | whitish, rather plump, hunched posture | yellowish-white | white, cylindrical, hunched posture |
| Grubs size | seemingly ten segments | to five centimeters | to five centimeters | comparable to the cockchafer | larger than typical grubs, up to 12 centimeters |
| classification | pest | pest | Beneficial organism | pest | protected beneficial organism |
Way of life and reproduction
Scarab beetles show very different ways of life and dietary preferences. In addition to the white grubs that live on plant roots, there are species that mainly live on dead wood or collect dung. The last-mentioned group includes, for example, the various dung beetles or the species known as "pill-turning". Some Scarabaeidae are extremely useful in the garden - such as the rose beetles or rhinoceros beetles - others cause considerable damage. Many scarab beetles are nocturnal or active. only wake up at dusk.
Development of the larvae
The life cycles and the development of the larvae also differ greatly between the individual species. The following table shows the main differences between the garden pests cockchafer and junior beetle:
| Cockchafer | June beetle | |
|---|---|---|
| Egg laying | May to June | June to July |
| Larvae hatch | end of June | end of July |
| Pupation | July August | August September |
| Duration of the larval stage | 3 to 5 years | 2 to 3 years |
| Adult beetles hatch | April to May | May to June |
Larva, pupa, and beetle - All beetles go through these steps
Another characteristic of many scarab beetle species is the fact that the larvae sometimes stay in the ground for years. The grubs only pupate after two to five years and only then hatch as adult beetles in spring. However, the adult animals known as imago do not live too long: May and June beetles usually do not get older than four to six weeks and usually only lay eggs once. For this reason, an infestation often only occurs every year - cockchafer, for example, plague gardeners about every four years.
background
Cockchafer or June beetle?
- Cockchafer: sideways, meandering
- June beetle: crawling on his stomach
- Rose chafer: on the back, caterpillar-like
The larvae of the rhinoceros beetle, on the other hand, are easy to recognize by their size.
frequently asked Questions
What to do if scarab beetles get lost in the apartment?
If a May or June beetle gets lost in the apartment, you can simply catch it and release it outside through a window. The animals will very likely mistake you or your furniture for a tree and land on it quickly. Scarab beetles are neither dangerous nor poisonous to humans.
How long do scarab beetles live?
While the beetle larvae - depending on the species - remain in the ground for up to four years, adult scarab beetles are usually not granted a long life. May and June beetles, for example, fly for four to six weeks at the most and then die immediately after they lay eggs.
Can scarab beetles bite?
If you have a May or June beetle on your arm and annoy it, it can bite painfully. However, this only happens very rarely and is completely harmless.
Tips
Plant garlic in between your flower beds as well delphinium and Geraniums (d. H. Pelargoniums, which are better known as balcony flowers) and thus prevent grub infestation. The animals don't like these plants and try to avoid them.