Hazelnut wrench
| Hazelnut wrench | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
.jpg)
Hazelnut borer ( Curculio nucum ) |
||||||||||||
| Systematics | ||||||||||||
|
||||||||||||
| Scientific name | ||||||||||||
| Curculio nucum | ||||||||||||
| Linnaeus , 1758 |
The hazelnut borer ( Curculio nucum ) is a beetle from the family of weevils (Curculionidae).
features
The beetles have a body length of 6 to 8.5 millimeters. Their bodies are black, white and gray-brown, with the whitish scales larger than the rest and forming spots. The wing top seam is provided with longer, protruding hairs that form a characteristic comb. The scutellum is as wide as it is long and has white scales. It has a bare hem on the side. The antennae and legs are red-brown, the latter are densely hairy whitish. The antennae is located in the middle of the trunk. The flagellum limbs are hairy protruding longer. The thighs ( femora ) of the front legs have a clearly recognizable tooth. The proboscis of the males is shorter than the body of the females. The species can be confused with the acorn borer ( Curculio glandium ), whose wing cover seam has no crest. Its flagellum limbs are longer than wide and only loosely, finely haired.
Occurrence and habitat
The species is distributed from Europe over the Caucasus to the Middle East and Syria as well as in North Africa. It is absent in the north of Fennoscandinavia ; in England and Scotland it only appears locally. The species is common in Central Europe and occurs from lowlands to mountains.
Way of life
The adults feed on young fruits of cherries, pears and similar plants in early spring and only eat hazelnut later . There they eat leaves and drill young nuts. The females lay their eggs in the nuts, which are then bitten open. Usually only one egg is laid per nut, and there are rarely several. The larvae feed on the inside of the nut for about four weeks, which falls off the plant as a result of the infestation. The adult larvae leave the nut to hibernate in the ground and only pupate there in spring. Sometimes they spend up to three years in the pupal stage before the adults of the new generation hatch in summer and later overwinter.
Combat
Since the hazelnut borer is not limited to the hazelnut tree, but also tamper with the fruits and leaves of other trees, especially fruit trees, when there is heavy infestation, they can become a nuisance in cultivated plantations. There are special insecticides for commercial cultivation, but they are not approved for home gardens. Appropriate prevention is effective here:
- Early-ripening varieties should be given preference when planting because they are less susceptible.
- Grow the hazelnut tree as a single high trunk. This makes it possible to attach a glue ring to the trunk for biological pest control.
- Regularly shaking off and collecting the beetles.
- Check the nuts regularly for holes in May and June and remove damaged nuts immediately.
- A calcium cyanamide fertilizer applied in spring acts against the larvae that overwinter in the soil.
- It is possible to use parasitic nematodes, which kill the larvae in the soil.
- Chickens can also be used as pesticides to eat larvae and beetles.
supporting documents
literature
- Karl Wilhelm Harde, Frantisek Severa and Edwin Möhn: The Kosmos Käferführer: The Central European Beetles. Franckh-Kosmos Verlags-GmbH & Co KG, Stuttgart 2000, ISBN 3-440-06959-1 .
- Jiři Zahradnik, Irmgard Jung, Dieter Jung et al .: Beetles of Central and Northwestern Europe. Parey, Berlin 1985, ISBN 3-490-27118-1 .
Web links
Individual evidence
- ↑ Hazelnut borer at insektenbox.de, accessed on August 18, 2019.
- ↑ Fighting the hazelnut borer - effective tips for prevention & control presented at gartentipps.com, accessed on August 18, 2019.