The hazelnut is a native tree that is well adapted to environmental conditions. It is rarely attacked by pests. However, there are some species that can occasionally or frequently be observed on the bush. In most cases, control is not necessary.
What pests occur on hazelnut bushes and how do you combat them?
Typical pests on hazelnut bushes are the hazelnut borer, the hazelnut bud gall mite and hazelnut aphids. To reduce infestations, collect fallen nuts, use nematodes, encourage natural enemies, and cut off infected buds.
These are typical pests:
- Hazelnut borer: occurs very often on trees
- Hazelnut bud gall mite: is of medium importance as a pest
- Hazelnut aphids: are among the occasionally occurring pest insects
Hazelnut drill
The female insects place their eggs in the unripe hazelnuts using an ovipositor. One larva develops per nut and, after hatching, eats the kernel. A small puncture mark indicates an infestation in the early stages. Adult hazelnut borers feed on the leaves. As soon as the fruits fall to the ground and the beetle larvae are fully grown, they enlarge the puncture and burrow into the soil, where they overwinter.
What you can do
Spread a plastic fleece under the hazelnut bush from the end of August. This will prevent the maggots from retreating into the substrate. Check the ground daily for fallen nuts and dispose of them with household waste. To kill the pests in the soil, SC nematodes (€12.00 on Amazon) have proven to be helpful. These will be administered via irrigation water from September. The measures will significantly reduce the infestation of these weevils next year.
Hazelnut bud gall mite
The so-called round buds are typical of a pest infestation. The gall mites attack fresh buds from June to July. Their larvae induce the formation of gall-like structures reminiscent of Brussels sprouts. The galls serve as overwintering quarters for the mite larvae. The bud leaves are often splayed, with bud development stagnating. They enlarge during the winter months by sucking. From May onwards, the stunted plant parts dry out. Occasionally the harmful insects also attack flowers.
What helps against it
Predatory mites such as Kampimodromus aberrans and coryli are among the natural enemies. Hazelnut gall mites do not typically occur in large populations. They affect individual buds so that the shrub does not suffer major damage. In most cases it is sufficient if you cut off the affected buds and dispose of them with household waste.
Hazelnut aphids
Aphids settle on the undersides of leaves and young shoots in spring and summer. Their body is yellowish and transparent or pale green in color, so that the pests are well camouflaged. Their sticky secretions, called honeydew, provide an indication of pest infestation. These thick 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 ladybirds, lacewings and parasitic wasps in your garden. The more diverse the fauna is, the better a natural balance can be established and pests are automatically decimated.
