The Content Of The Article:
- What are grubs?
- Useful beetle larvae
- Harmful species
- How do you differentiate the species?
- Endangered plants
- Prevent damage
- Fight grubs
What are grubs?
As grubs, the larvae of certain beetle species from the known superfamily Scarabaeoidea (leafcorn beetle) are called. These include, for example, the cockchafer (Melolontha), the rose beetle (Cetoniinae) and the rumped brown beetle (Amphimallon solstitiale). The name Engerling comes from Middle or Old High German and means something like "little worm" or "Made".
The fleshy animals reach as larvae a length of up to six centimeters. The thick body is light gray to orange brown colored, some species even show a completely black color. Engrins can also be recognized by their distinct head and strong mouthpiece. The abdomen of the animals is thickened, in front there are three strong pairs of legs, which help them dig in the ground. Grubs feed on, among other things, decomposing plant substances, but also partially on living roots.
There are four major species in our gardens, but they rarely cause much damage. Among them are the grubs of the rose beetle, the rhinoceros beetle, the May beetle and the Junikäfer (also: brown beetle).
Depending on the species, the animals can survive as larvae in the soil for up to four years. An acute infestation with Engerlingen falls to the hobby gardener usually only late, namely, when the plants threaten to enter due to lack of roots. In many cases, the animals are only discovered by chance when digging up the garden. Adult beetles, however, fall faster in the garden. Since the beetles only become active when twilight sets in, they are usually seen flying in the early morning or late at night.
Useful beetle larvae
Not all the grubs that accumulate in the garden are harmful. Some species, such as the rhinoceros beetle or the rose beetle larvae, can even be of great use.
Nests of rhinoceros beetles are up to ten inches tall and are therefore very noticeable. They are missing in contrast to other Engerlingen the so-called row of thorns on the abdomen. Since the larvae prefer dead wood as food, they are one of the useful beetle larvae. As there is less and less natural deadwood in our forests, there is a decline in these beetle larvae. The use of bark mulch and the ever warmer climate promote the spread of the rhinoceros beetle on the other side.
The larvae of the rose beetle are also among the useful grubs. They reach a length of almost three centimeters and are quite thick. Since these grubs feed only on dead roots and other dead material, they do no harm in the garden. Living plants are not part of their diet. The adult beetle is metallic gold-green, its underside is purple. Their flight time is in May and June. The beetle larvae, in interaction with fungi and bacteria, for example in compost, promote the decomposition of organic matter. Thus, they make an important contribution to the formation of useful humus. During their special digestive process, so-called permanent humus forms - a humus form of hard-to-decompose humic substances. The nutrients found in the humus are released slowly and moderately to the plants. The generation period of the beetle larvae is two to three years.
Birds like the starling (Sturnus vulgaris) belong to the natural enemies of the grubs
Probably the most harmful and well-known grubs in our latitudes are those of the May beetle. This grunt reaches a length of about three centimeters and can survive between three and four years in the ground. It damages plants mainly through its feeding activities at the roots. This happens mainly in the second year of life. In the third year, the grub usually retracts up to 60 centimeters deep into the ground, where it subsequently pupates. The adult beetle slips underground in the same year, but leaves its place there only in the following May.
Even the grub of the brown beetle is not uncommon in our gardens. This beetle lifts off the lawn in large quantities on warm evenings in June or July. He is only about half the size of the adult cockchafer, the grubs of both species, however, are about the same size and therefore visually hardly distinguish each other. The beetle larvae of the beetle feed mainly on grass roots. They have a generation period of about two years.
Another undesirable and frequent guest in the garden of many hobby gardeners is the grub of the garden gullet. The beetle itself is very small, the grubs are about one centimeter long. Garden Leavens fly over the lawn in May and June. Grubs of this species love turf roots. Their generation time is relatively short and lasts only one year.
How do you differentiate the species?
The adult beetles can be easily distinguished from each other, the grubs of the individual species vary visually but hardly.
The three best known species of grubs, however, can be distinguished by their different modes of locomotion: Grubs of the May beetles meandering sideways. Those of the Junikäfer perform creeping movements in prone position and those of the rose beetle move in the supine position.
Depending on the species different plants are attacked by Engerlingen. For example, larvae of the garden beetle damage primarily the lawn. In an acute attack, the roots of the grasses are completely eroded, so that the lawn can be almost completely pulled off by hand. However, a heavy infestation is quite rare. Young plants, potatoes, turnips, strawberries and lettuce are also very high on the menu of pests.
Preventive measures are the most effective protection against grubs. First, it is recommended to avoid nocturnal lighting of the property, as the beetles feel attracted to light sources in the dark. This encourages oviposition in this environment.
On the other hand, the hobby gardener can design insect screens. Spread suitable nets over your beds and over your compost. In this way, an oviposition of the adult beetle is also avoided. A year-round coverage is not necessary. Use the nets only in the time of the beetles - ie between May and June - and, if you discover striking numbers of beetle larvae in the immediate vicinity.
Also deeply embedded curb stones in the lawn, a close-meshed root protection grid and wire inserts prevent infestation by Engerlingen. A disadvantage of these methods, however, is that a large amount of work is required in large gardens.
The regular working of the lawn with a scarifier loosens the soil, making it less susceptible to the settlement of the beetle larvae. This approach ensures that the grubs do not find suitable livelihoods and avoid the garden. Also, a manual loosening of your garden floor is recommended.
The same applies to a thorough care of your property. Weed weeds at regular intervals and destroy dead plant parts.
Engerling infestation is often brought under control, if you simply remove the pests immediately by hand
A damage caused by grubs in the garden usually has only small dimensions. A fight must be initiated only when the small larvae spread rapidly.
If you find grubs when digging up your garden, it's best to collect them by hand. Especially after a heavy rain fall, when the soil is particularly soft, grubs like to show up on the surface of the soil and are easy to find. The harmless grubs, such as the rose beetle, of course, do not have to be collected.
Some plant species have a deterrent effect on grubs. These include, for example, delphiniums and geraniums. The plants have proved to be particularly useful as they are poisonous to the small larvae. If necessary, plant them in large numbers in your garden. Not poisonous, but also deterrent to the animals acts garlic.
Also, the use of nematodes (roundworms) helps in the control of Engerlingen. Nematodes act in a natural way and can be used sustainably. Among other things, they can be bought on the internet, their application is quite simple. A pack of nematodes for a lawn of about twenty square meters costs about 13 euros.
In addition, it is very helpful to welcome and keep natural enemies of terrestrials such as birds, shrews, hedgehogs and moles in their garden. The beneficials can be recognized by numerous holes in lawns and flowerbeds. What seems hobby to the hobby gardener at first turns out to be very useful in the long run. Because the animals feed on the juicy larvae with a great preference and dig for the soil after the delicious and nutritious meal.