Lesser stag beetle

The lesser stag beetle (Latin: Dorcus parallelopipedus) belongs to the Lucanidae family within the order Coleoptera. While it is not always classified as a primary agricultural pest, it acts as a significant wood-boring insect that affects both wild forest trees and fruit trees in commercial or private orchards.

This beetle primarily attacks hardwood trees, including oak, beech, elm, apple, and pear. The larvae show a strong preference for decaying wood, occupying stumps, rotting trunks, or damaged parts of living trees, where they feed on the cellulose and lignin within the softened wood tissue.

The life cycle is long, typically lasting several years during which the larva lives inside the tree wood. The adult stage occurs in the warmer months. These beetles are generally nocturnal, and during the flight season, they may visit trees to feed on tree sap, which can sometimes introduce fungal pathogens into the tree's vascular system.

The damage caused is characterized by the internal tunneling of larvae. This activity compromises the structural integrity of the tree and disrupts nutrient transport within the phloem and xylem. For old fruit trees, such infestations lead to a noticeable decline in vigor, loss of productivity, and eventually tree death if the infestation is severe.

Effective management strategies include cultural practices to discourage infestation:

• proper site sanitation, including the removal of old stumps and decaying wood debris;
• regular pruning to eliminate dead or heavily damaged branches where larvae might hide;
• promoting tree health through proper fertilization and watering;
• sealing cracks and bark injuries to prevent female beetles from accessing suitable egg-laying sites.