The hazelnut is a native tree that is well adapted to the environmental conditions. It is rarely attacked by pests. However, there are a few species that can be observed occasionally to frequently on the bush. Fighting is usually not necessary.
The female hazelnut borer bores holes in hazelnuts to lay her eggs
These are typical pests:
- hazelnut borer: occurs very frequently on the trees and shrubs
- Hazelnut bud gall mite: has a medium importance as a pest
- Hazel aphids: belong to the occasional harmful insects
hazelnut borer
The female insects place their eggs in the unripe hazelnuts with a ovipositor. A larva develops for each nut, which eats the kernel after hatching. A small puncture mark indicates an infestation in the early stages. Adult hazelnut borers feed on the leaves. Once the fruit has fallen to the ground and the beetle larvae have grown, they enlarge the hole and burrow into the soil, where they hibernate.
What you can do
From the end of August, spread out a plastic mat under the hazelnut bush. This will prevent the maggots from retreating into the substrate. Check the floor daily for fallen nuts and dispose of them with household waste. SC nematodes have proven helpful in killing the pests found in the soil. These are administered via the irrigation water from September. The measures will significantly reduce the infestation by these weevils next year.
Hazelnut bud gall mite
The so-called round buds are typical of a pest infestation. The gall mites infest fresh buds from June to July. Their larvae induce the formation of gall-like structures resembling Brussels sprouts. The galls serve as winter quarters for the mite larvae. The bud leaves are often splayed, with bud development stagnating. They increase in size during the winter months through sucking activity. From May the stunted parts of the plant dry up. Occasionally, the harmful insects also attack flowering plants.
What helps
Predatory mites such as Kampimodromus aberrans and coryli are natural enemies. Hazelnut gall mites do not usually appear in large populations. They affect individual buds so that the shrub does not suffer any major damage. In most cases it is sufficient if you cut off the affected buds and dispose of them in the household waste.
Hazel aphids
Aphids settle on the undersides of leaves and on young shoots in spring and summer. Their body is yellowish and transparent or pale green in color, so the pests are well camouflaged. Their sticky secretions, known as honeydew, give an indication of pest infestation. These viscous coatings form a breeding ground for sooty mold fungi.
Does fighting make sense?
Since the plant sap suckers are not dangerous to the hazelnut bushes, control is not necessary. Instead, encourage natural enemies such as ladybugs, lacewings and parasitic wasps (€22.99) in your garden. The more diverse the fauna, the better a natural balance can be established and pests are automatically decimated.