Two-spotted weevil

Systematic position: Cossonus bimaculatus is a species of beetle belonging to the order Coleoptera and the family Curculionidae. These weevils are specialized wood-boring insects, often referred to as bark-dwelling weevils, which play a significant role in forest ecology by interacting with dying or stressed tree tissues.

Host plants: The primary hosts for this pest are coniferous tree species, most notably pine and spruce. While the beetles prefer decaying or damaged wood, high population densities can occasionally lead to attacks on trees that are showing early signs of physiological decline, making them a concern for forest health management.

Biology and life cycle: The life cycle of Cossonus bimaculatus is closely linked to the wood it inhabits. Adult beetles lay eggs under the bark of host trees. The larvae emerge and start feeding on the inner bark and phloem, creating complex tunnels that run longitudinally along the tree trunk. The maturation process, including pupation, occurs within the bark or the surface layers of the wood.

Damage and economic impact: The damage is primarily caused by larval feeding, which disrupts the tree's nutrient transport system by destroying the cambium. This action often leads to the death of the affected tree section or the entire tree. Heavily infested trees show signs of decline, such as yellowing foliage and the presence of fine wood dust and boreholes on the trunk surface.

Protection measures: Effective control relies heavily on silvicultural practices, particularly the removal and destruction of infested wood before the new generation of adults emerges. Maintaining forest hygiene and removing debris are critical. In specialized plantations, pheromone traps can be used for monitoring, and in severe cases, the selective use of targeted insecticides may be necessary to protect high-value timber or decorative specimens.

• Sanitary cutting of infested trees
• Monitoring with pheromone traps
• Maintaining stand health and vigor
• Removal of logging residues