Birch Bark Beetle

Birch Bark Beetle (Scolytus ratzeburgi). This beetle belonging to the bark beetles family (Scolytidae) is common on birch trees from May through June. The Birch Bark Beetle measures 4 to 7 mm, is dark brown and lives off the sap of the living tree.
The female gnaws an up to 15 cm long tunnel just below the bark (main tunnel). On either side of the main tunnel, the female lays eggs. The larvae from the eggs gnaw long tunnels across the trunk, creating a symmetrical chewing pattern – characteristic of bark beetle chewing trails. The fully grown larvae pupate and emerge as beetles after a few weeks. The young beetles bore their way out.
The birch bark beetle, like other bark beetles, is harmful because the water supply is blocked by the tunnels under the bark, causing the tree to die.