All information about the white grubs

the essentials in brief

• The cockchafer larva is considered harmful because its diet consists of plant roots.
• Mass deposits with devastating damage are a thing of the past.
• Nematodes fight local infestation with cockchafer grubs without poison. Ecological gardening is the best prevention.

Cockchafer larva - pest or beneficial?

The cockchafer larva owes its bad reputation to its menu. Plant roots of all kinds are an essential part of the diet of cockchafer grubs. A grub spends between three and five years of its development deep in the ground, feeding on roots. The cockchafer larva owes its status as a pest to this unfortunate diet. Dramatic crop losses or serious forest damage are only to be complained about in the case of mass occurrences with a population of 100 to 200 larvae per square meter.

The days of devastating damage from cockchafer larvae are long gone. In many places, only the grandparents have seen a cockchafer plague. Until the 1960s, there was even a so-called cockchafer year, so that the children could collect beetles and larvae. Today children and young adults may still know the Beetles from “Max and Moritz” by Wilhelm Busch or as a Sumseman from “Peterchens Mondfahrt”.

Punctual infestation cannot be ruled out

Locally, cockchafer larvae give hobby gardeners a headache when nests with a dense swarm of white grubs form in the bed or under the lawn. An infestation can be recognized by the poor growth of perennials, shrubs and trees. Yellow spots appear on the lawn, which gradually enlarge and dry out. Against this background, it is of little consolation for the gardener concerned that cockchafer ladies are available In particular, prefer garden soils as a nursery that are ecologically managed in an exemplary manner will.

Fight cockchafer larvae with beneficial insects - this is how it works

Did you find a single cockchafer larva? Then this is an occasion to search the bed or lawn thoroughly for more specimens. If you find large numbers of grubs or uncover entire nests under the lawn, control measures are an option. To prevent the infestation from spreading into a nuisance, it is not necessary to use chemical poison. Instead, you fall back on the powerful help of roundworms of the genus Heterorhabditis. How to combat cockchafer larvae with beneficial insects:

1. The best time to combat is 6-8 weeks after the flight time
2. Buy fresh nematodes (e.g. B. 12 million for 24 m²) as well as watering bars for application with the watering can
3. Nematodes im Clay granules Dissolve in water according to the supplier's instructions
4. Water the infested area with nematode water
5. keep the treated soil constantly slightly moist for 6 to 8 weeks
6. Do not lime the bed or lawn before or after (Fertilize does not disturb roundworms)

The nematodes, which are around 1 mm in size, actively search for cockchafer larvae and invade the body. There the beneficial insects give off a bacterium that is poisonous for the grubs. The larvae are destroyed within 2 to 3 days. The roundworms have grubs from Cockchafer and June beetle equally in sight. Pupated larvae and adult beetles do not belong to the nematode prey scheme.

Only with emergency approval - soil fungus kills cockchafer larvae

Fungal infections kill cockchafer excruciatingly

When looking for alternatives to DDT and other poisons against cockchafer larvae, the scientists found what they were looking for in soil fungi. Beauveria brongniartii has been useful in the fight against large numbers of white grubs and cockchafer for more than 100 years. The fungus infects its host with spores, which neither larvae nor adult beetles can survive.

The pesticide is applied in the form of grains that have grown over with the fungus. The spores form at a depth of 5 to 10 centimeters and infect existing cockchafer larvae. In Germany, the use of the agent still requires an emergency approval. In Austria, the preparation is available on presentation of a plant protection certificate. Switzerland has approved the product for use in allotment and home gardens.

Digression

Rose beetle larva or cockchafer larva?

Prevention is the best fight

Hedgehogs love larvae and grubs

Targeted prevention can successfully avoid direct exposure to cockchafer larvae. A wide range of effective methods is available for this purpose, so that female cockchafer do not lay their eggs in the bed or lawn in the first place. This is how it works:

Mosquito nets

After the last frost, the starting signal for the main flying time of cockchafer is given. Now the finished beetles leave their pupal shell, in whose protection they spent the winter. Males and females do not hesitate to start a family. The winged girls are mated within a short time and are looking for a place to lay their eggs. By covering the garden with insect protection nets, you thwart the beetle ladies. In the course of global warming, the preventive measure should be noted in the calendar for the beginning / middle of April.

Attract natural enemies

The declared enemies of cockchafer grubs include moles, Hedgehog, Badger, star and crow. Numerous other biological opponents like to eat the juicy larvae. Suitable framework conditions are advantageous so that the predators can gather in the garden and hunt the cockchafer larvae. The following tips & tricks may inspire you for a natural garden, in which harmful cockchafer larvae and other grubs have bad cards:

• consistent avoidance of pesticides
• Garden design with wild corners, piles of leaves, rotten tree trunks as places of retreat
• Mixed and Benjes hedges create as hiding places for beneficial insects

Keeping chickens and Ducks is one of the most effective control methods in the natural garden. Picking chickens and busy ones Ducks discover every little cockchafer egg and grub in no time. A positive side effect is that ducks thwart the plans more voraciously Nudibranchsto get to grips with flowers, shrubs and vegetables.

Scarify the lawn

Regular scarifying prevents infestation by grubs

The lawn is a popular place for female cockchafer to place their eggs. A well-kept green area with dense Sward However, it is not welcomed by the beetle ladies. Regular Scarifying is one of the smart preventive measures against white grubs, especially since the best date falls when the eggs are laid. Of the Scarifier(€ 98.00 at Amazon *) not only combs out lawn thatch and makes space for strong noble grasses. Cockchafer eggs that have already been laid are also destroyed.

Lawn protection fabric

If you are new to a lawn invest, the investment in a protective fabric between the coarse subgrade and fine subgrade is worthwhile. This precaution is always advisable if you or your neighbors have ever struggled with increased numbers of cockchafer. This preventive measure has its price. In return, you don't just ward off cockchafer larvae. More uninvited guests like moles, also stay away from your lawn carpet.

background

Mass occurrence every 30 to 45 years

Cockchafer larva in portrait - profile to get to know

Cockchafer larvae can grow up to 5cm

The development of a cockchafer larva begins as a tiny, 3 mm long, yellowish colored egg. When the larva hatches from the egg after 4 to 6 weeks, the parents have long since blessed the time. Male cockchafer die immediately after mating. Females carefully choose different locations to lay 15 to 100 eggs about 10 cm deep in the ground. With this work, female cockchafer have fulfilled their purpose in life and also die. The following profile summarizes important properties of white grubs:

Immediately after hatching from the egg, cockchafer larvae begin to eat. In the first few days, the grubs mainly eat sludge and delicate roots. In proportion to their growth, the larvae feed on thicker roots, which they locate with the help of root excretions. A powerful mouth tool allows the insatiable larvae to attack almost all plant roots in the soil. When it is drought, grubs look for deeper layers of soil with a higher moisture content. Damp weather lures them to higher layers, but not to daylight.

frequently asked Questions

Are cockchafer larvae poisonous?

Hobby gardeners and forest owners chalk up cockchafer larvae that plant roots are at the top of the menu. Depending on the population in the garden or forest, the insatiable grubs leave damage to all kinds of shrubs and trees. While herbaceous plants and deciduous trees grow after being eaten above ground by adult cockchafer can recover, cockchafer grubs deprive the plants of their livelihood without any prospect of it Regeneration. The harmful effect is based on the insatiable appetite. Cockchafer larvae do not release toxic substances to the plants or the soil.

There is a cockchafer larva in our garden. How long does it take to develop from the grub to the finished cockchafer?

A cockchafer larva spends three to five years in the ground. On average, it takes four years to develop from a newly hatched white grub to a winged cockchafer. During this time, the diet consists exclusively of the roots of flowers, shrubs and trees. Under favorable conditions, a cockchafer larva overwinters twice and pupates in August of the third Year, hibernates in the doll's cradle and flies out of the ground in April or May of the fourth year as finished beetle.

Are there manual methods of combating local infestation with cockchafer larvae in the flower and perennial beds?

If you suspect that cockchafer larvae are frolicking in the bed, dig up the affected plants and their roots. Collect by hand all the grubs that you discover in the root network. You cannot be sure that you have got hold of all the cockchafer larvae. For this reason, we recommend planting the plants again in the bed in a spacious pot with fresh substrate. In this way, hidden specimens cannot spread further in the garden.

We are fighting in the garden with high numbers of cockchafer larvae. Shouldn't we just mill the contaminated soil?

Only when all control methods fail should the use of a tiller against cockchafer larvae be considered. The tiller plows through the earth to a depth of 10 centimeters and destroys all grubs. Further control agents are no longer required. However, all other soil organisms also have to pay for the radical tillage with their lives. Furthermore, the soil structure is completely destroyed. The subsequent regeneration takes a long time.

Tips

The fight against a gigantic population with billions of cockchafer in Avignon, France, was unsuccessful. In 1320 the pests were ordered by court order to “withdraw within three days on a by boards marked field where there is enough food for them. "Offenders would be treated as outlawed and exterminated, it went on. Although the announcement shows the first signs of an ecological stance, the measure came to nothing.