• Longhorn beetles
• Oak processionary caterpillar
• Oak bark beetle
• Pear jewel beetle

Longhorn beetles (Cerambycidae) are beetles notable for their long antennae, often longer than their bodies. They occur worldwide and play a role in the breakdown of dead wood. Some species, such as the house longhorn beetle, can cause serious damage to timber structures as well as to living trees. The white larvae bore deep into the wood, and their network of tunnels leads to weakening of the plant material. Especially in recent planting, it is important to detect longhorn beetle activity in time. In order to determine appropriate control measures, knowledge of the behaviour and life cycle of longhorn beetles is crucial for the preservation of healthy trees. It is also important to follow the planting instructions carefully in order to ensure proper planting. An infestation can be observed on the trunk, thick branches and also at the root collar. Here, round to oval bore holes with a diameter of between 5 and 10 mm may be visible. Bore dust and sawdust worked out of the galleries by the larvae can also be found. In the crown of the tree, discolouration, fallen leaves or dead branches may be seen. To protect the tree against longhorn beetles, it is advisable to apply ESK to the bark, especially during the first two years. This product acts as a natural deterrent and gives off a distinctive smell that repels the insects. The product is composed of various plant extracts bound with a natural adhesive. It must be applied before the beetle reaches the tree.

Newly planted oaks are often under stress as a result of transplanting, which makes them a ready target for the oak bark beetle. The oaks release a stress hormone that attracts the beetles. The oak bark beetle (Scolytus intricatus) is a small beetle measuring 3 to 4 mm, with a shiny dark brown to black wing case. It attacks weakened oaks, bores through the bark and then feeds short, horizontal galleries into the living wood, across the grain of the bark. In this maternal gallery, the beetle lays its eggs. The larvae that hatch from these eggs feed long new galleries at right angles to the maternal gallery and pupate at the end of them. Once they emerge, the young beetles finally bore their way out of the tree through the bark, after which the cycle begins again. To ensure that a tree experiences much less stress in its first year, we recommend pruning it ready for planting. This is certainly advisable with oaks. Pruning ready for planting means that about one third of the lateral branches in the crown are cut back. This keeps the root-to-crown ratio in balance, so that the tree loses less water through the leaves and experiences less stress. Because water shortage makes newly planted oaks more susceptible to infestation, sufficient watering should be provided during dry periods.