Even if it is relatively small, the bark beetle can cause a lot of damage. It rarely occurs individually; several thousand specimens can live on a single spruce tree. Unfortunately, fighting it is not that easy.
How do I recognize a bark beetle infestation on my spruce?
To recognize a bark beetle infestation on a spruce, look for fine brown bore dust on the trunk, resin droplets and light spots on the bark. When needles change color or the bark falls off, control is often almost impossible.
Contrary to what is often assumed, the bark beetle does not only occur in the forest, it can also attack your spruce tree in the garden. Dryness and warmth cause the pest to spread massively. If a hot, dry summer is followed by a mild winter, the risk of an infestation is particularly high. Often three generations appear within a year instead of the usual two.
Are there different types of bark beetles?
Basically there are two different types of bark beetles, the bark breeders (larvae feed on the bark) and the wood breeders (larvae live in the wood). The most common species of spruce are the book printer (Ips typographus) and the engraver (Pityogenes chalcographus).
Both species belong to the bark breeders. A severe infestation inevitably leads to the death of the spruce. The closer your property is to a spruce forest, the higher the risk of a bark beetle infestation. However, in an ideal location, a spruce rarely gets sick.
How do I recognize a bark beetle infestation?
The first sign of a bark beetle infestation is usually fine brown drill dust at the foot of the spruce. If you discover this you must act quickly. Resin droplets on the trunk and light spots on the tree bark also indicate bark beetles. When the needles change color or the spruce loses its bark, it is often too late for successful bark beetle control.
What can I do against bark beetles?
The affected spruce can hardly be saved, at best if only a single branch is affected. However, this rarely happens. Infected branches must be removed and disposed of properly. Burning is the best way to prevent the beetles from spreading and moving to other trees.
Insecticides only help to a very limited extent or not at all. Their use should be carefully considered; in severe infestations it is definitely not enough. An infected spruce tree must be felled immediately and its bark removed as quickly as possible so that the beetles cannot spread to the neighboring trees.
The most important things in brief:
- Dry and warm weather increases the risk of bark beetle infestation
- weakened spruces are particularly vulnerable
- The first sign of an infestation is often brown drill dust on the trunk
- now often 3 instead of 2 generations per year
- Lifespan of a bark beetle: approx. 1 year
- Book printer: bark beetle that specializes in spruce trees
- infected tree can hardly be saved
Tip
Inform the forestry authority if you have bark beetles in your garden so that they do not become a pest.