Coarse sawyer

Systematic position: The coarse sawyer (Monochamus scabiosus) belongs to the order Coleoptera and the family Cerambycidae, commonly known as longhorned beetles. This species is recognized as a significant technical pest of timber, widely distributed across the forest ecosystems of East Asia, including the Russian Far East, China, and Japan.

Host plants: The primary hosts for the larvae of this beetle are coniferous trees. The pest shows a strong preference for fir, spruce, and pine species. It frequently attacks weakened, dying, or freshly felled timber, causing substantial economic loss by compromising the structural integrity and quality of the wood.

Biology and life cycle: The insect's life cycle is strictly dependent on the health status of the host trees. Females deposit eggs under the bark after creating small incisions. Upon hatching, the larvae initially feed on the phloem before boring deep into the xylem. Pupation takes place within the wood, and adult beetles eventually emerge through characteristic oval-shaped exit holes.

Nature of damage: The damage caused by the coarse sawyer is severe due to the deep penetration of the larvae into the trunk. By constructing extensive galleries within the wood, they destroy the timber's quality. Furthermore, these tunnels facilitate the entry of wood-decay fungi, which significantly accelerates tree decline and wood degradation.

Control measures: Management of this pest requires an integrated approach combining silvicultural practices and sanitation. The most critical control measure is the prompt detection, logging, and disposal of infested trees before the adult beetles emerge. For stored timber, chemical treatment or storage in dry, unfavourable conditions for the beetle is recommended to prevent infestation.

• Execution of sanitary logging in affected forest areas.
• Deployment of pheromone traps for population monitoring.
• Rapid transport and processing of harvested timber.
• Application of protective chemical treatments to wood products.