Brown pine borer

Systematic position: the brown pine borer (Arhopalus unicolor) belongs to the order Coleoptera and the family Cerambycidae, commonly known as longhorn beetles. It is a wood-boring insect that plays a significant role in the decomposition of coniferous forest materials.

Host crops and damage: the primary hosts include Scots pine, spruce, and fir. The pest specifically targets stressed, dying, or recently felled trees. By tunneling deep into the sapwood and heartwood, the larvae compromise the structural integrity of the timber, significantly reducing its commercial value and accelerating tree decay.

Biology and life cycle: adult beetles are active during the summer. Females lay eggs in bark crevices or directly on decaying wood surfaces. Upon hatching, the larvae bore into the bark and eventually the wood, where they create extensive galleries. The life cycle typically spans one to two years, depending on the environmental conditions and the quality of the host material.

Character of damage: infestations are identified by the presence of oval exit holes on the surface of the trunk. Inside, the galleries created by the larvae are filled with fine wood frass. These extensive tunnels destroy the wood fibers, leading to a loss of strength and making the lumber susceptible to secondary infections by wood-decaying fungi.

Control measures: management focuses on preventative silvicultural practices. It is crucial to conduct regular sanitary thinning and remove windthrown or dead wood from the forest before the adult beetle emergence. Proper storage of logs, ideally in well-ventilated areas off the ground, is essential to minimize the risk of infestation in harvested timber.

• Regular forest health surveys and monitoring.
• Prompt extraction of infested or dying trees from the site.
• Barking of freshly cut logs to prevent egg-laying.
• Application of insecticide treatments for high-value timber stocks.