Hazel bark beetle

Systematic position: The Hazel bark beetle (Dryocoetes coryli) belongs to the order Coleoptera, family Curculionidae, and subfamily Scolytinae. It is a specialized wood-boring insect that occupies a specific niche within the cambial layer of various deciduous trees.

Host plants: The primary host for this beetle is the common hazel (Corylus avellana) and various hazelnut cultivars. Additionally, the species can infest other broadleaved trees such as hornbeam, beech, and alder, especially when these trees are stressed or environmentally compromised.

Biology and lifecycle: The lifecycle of Dryocoetes coryli is tightly synchronized with the host tree's condition. Adult beetles overwinter under the bark or in forest litter. In the spring, they emerge to bore galleries under the bark of host trees. Females lay eggs, and developing larvae feed on the inner bark, eventually pupating within the gallery system before emerging as adults.

Damage and economic impact: The primary economic damage is caused by both adults and larvae feeding on the phloem and cambium. This feeding activity disrupts the transport of water and nutrients throughout the tree. Visible symptoms include canopy dieback, chlorosis of leaves, and thinning crowns. In severe cases, high infestation levels can cause the death of the entire plant.

Protection measures: Management of this pest focuses on sanitation and tree health. Removing and destroying infested wood before the beetles emerge is critical to preventing the spread. Maintaining vigorous orchards through proper fertilization and irrigation is essential, as healthy trees are better able to resist bark beetle colonization. In specific cases, targeted systemic insecticides may be used during beetle flight periods.