Läpikuoria

Läpikuoria, also known as the European pine sawfly, is a species of insect belonging to the family Tenthredinidae. It is native to Europe and parts of Asia, but has been introduced to other regions, including North America. The adult läpikuoria is a small, slender insect with a body length of about 10-15 mm. It has a distinctive appearance, with a black body and yellow or orange markings on the wings.

The larvae of the läpikuoria are the most damaging stage of the insect's life cycle. They feed on the inner bark and cambium layer of pine trees, causing significant damage. This feeding activity can weaken the tree, making it more susceptible to diseases and pests. The larvae also produce a substance called frass, which can clog the tree's vascular system, further exacerbating the damage.

The läpikuoria completes its life cycle in one year. The adult female lays her eggs on the needles of pine trees. The eggs hatch into larvae, which then burrow into the tree to feed. After several weeks of feeding, the larvae pupate in a cocoon within the tree. The adult insects emerge from the cocoons in the spring, completing the life cycle.

Control measures for the läpikuoria include the use of insecticides, but these are often ineffective due to the larvae's protected location within the tree. Biological control methods, such as the introduction of natural enemies of the läpikuoria, have shown some promise. Additionally, proper tree care, including proper pruning and watering, can help to reduce the impact of the läpikuoria on pine trees.