Four-toothed bark beetle

The four-toothed bark beetle (Pityogenes quadridens) is a member of the Curculionidae family and the Scolytinae subfamily. It is recognized as a significant stem pest that predominantly attacks coniferous forests, particularly in the European region, where it targets weak or stressed trees.

The primary host trees include various pine species (Pinus spp.), with a preference for young stands or the upper parts of the canopy in mature trees where the bark is thin. These beetles are highly sensitive to tree health and often colonize pines that have been damaged by drought, wind, or other forest insects.

Regarding its biology, the beetle overwinters in the forest floor or at the base of the trunk. Once spring temperatures rise, the adults emerge to seek new hosts. They construct star-shaped galleries in the inner bark, where the females lay eggs. The larvae then hatch and tunnel through the cambium layer, feeding on the tree's vital tissues.

The economic damage caused by Pityogenes quadridens is extensive, as their tunneling disrupts the vascular system responsible for nutrient and water transport. This results in crown discoloration (reddening), growth reduction, and the eventual death of the tree, which can lead to rapid infestation of neighboring healthy pines.

Effective management and control strategies include:

• early detection through systematic forest pathology surveys;
• sanitary removal of infested trees before the next generation emerges;
• disposal of infested bark or timber by burning;
• application of pheromone traps during peak flight periods;
• improving forest stand health through proper silvicultural practices.