Oak longhorn beetle

Systematic position: The oak longhorn beetle (Rhagium sycophanta) is a member of the Coleoptera order and the Cerambycidae family. It is recognized as one of the largest longhorn beetles in Europe, playing a notable ecological role, though it is often considered a secondary pest in managed forest stands.

Host plants: This insect predominantly infests species of the Quercus genus (oaks). While it shows a strong preference for oak trees with thick bark, it can occasionally be found on beech, hornbeam, and other broad-leaved trees. Healthy trees are rarely attacked, as the beetle prefers those already weakened by drought or other environmental stressors.

Biology and life cycle: The life cycle of Rhagium sycophanta typically spans two to three years. Adults emerge during the spring and are active until early summer. Females deposit eggs into deep bark crevices. Upon hatching, larvae feed extensively on the phloem and cambium. Before pupation, the larvae burrow into the sapwood to construct a distinctive pupal chamber lined with coarse wood fibers.

Damage patterns and economic impact: Damage is caused exclusively by the larval stage. By feeding beneath the bark, they disrupt the tree's vascular system, leading to bark necrosis and severe weakening of the tree's vigor. Repeated or dense infestations often facilitate the entry of secondary pathogens, significantly reducing timber quality and leading to the eventual death of mature trees.

Control measures: Management of this pest relies on integrated forest protection practices. The most effective methods include:

• Prompt removal and processing of infested or fallen timber during sanitary felling.
• Monitoring of forest health to identify stressed trees early.
• Maintaining biodiversity to encourage natural predators like woodpeckers and parasitoid wasps.
• Rapid extraction of harvested timber from forests before the spring flight period of the adult beetles.