Ash bark beetle

Taxonomy. The genus Hylesinus belongs to the order Coleoptera and the family Curculionidae, subfamily Scolytinae. These insects are well-known wood-boring pests that are highly specialized in attacking specific host trees within the forest ecosystem.

Host plants. These beetles primarily infest trees belonging to the Oleaceae family. The most significant damage is observed on various species of ash trees (Fraxinus). While they prefer stressed, damaged, or recently felled trees, high population densities can lead to attacks on healthy, vigorous specimens.

Biology and life cycle. The life cycle involves adult beetles boring through the bark to create maternal galleries. Eggs are deposited along the sides of these tunnels. Upon hatching, the larvae feed on the inner bark and cambium, creating galleries that effectively ring the tree and disrupt the flow of nutrients and water.

Nature of damage. The primary harm caused by Hylesinus is the girdling of the tree trunk, which leads to chlorosis, crown dieback, and eventually the death of the tree. Signs of infestation include small, circular entry holes in the bark and the presence of frass (boring dust) accumulating in bark crevices or at the tree base.

Protection measures. Effective control relies on sanitation logging and the removal of infested material before the new generation of adults emerges. Maintaining tree vigor through proper watering and soil fertilization reduces susceptibility. In high-value areas, targeted insecticide treatments applied to the bark during peak flight times can be highly effective.

• Implementing regular forest health inspections.
• Removing and destroying infested wood promptly.
• Using trap logs to aggregate beetle populations.
• Deploying pheromone-based monitoring systems.