Rosalia longicorn

Systematic position: The Rosalia longicorn (Rosalia alpina) belongs to the order Coleoptera and the family Cerambycidae. This striking beetle, characterized by its distinctive blue-grey color and black spots, is one of the most recognizable longhorn beetles in Europe and Asia.

Host plants: The pest primarily targets deciduous trees, showing a strong preference for beech, hornbeam, elm, willow, and walnut. In orchard settings, the Rosalia longicorn can pose a significant risk to weakened fruit trees such as apple, pear, and cherry, especially if these trees have been previously damaged or are exhibiting signs of decay.

Biology and life cycle: The life cycle of this insect typically spans 3 to 4 years. Adult beetles are active during the summer months and are most visible on sunny days. Females deposit eggs into cracks or crevices in the bark of suitable host trees. Upon hatching, the larvae bore into the wood, where they feed on inner tissues for several years before pupating.

Nature of damage and harmfulness: The primary damage is caused by the larvae, which tunnel deep into the wood, compromising the tree's internal structure and circulation. This leads to reduced vitality, premature drying of branches, and increased susceptibility to secondary infections. Adult exit holes are visible signs that indicate the presence of an infestation within the wood.

Control measures: Protecting trees from the Rosalia longicorn relies on early detection and preventative maintenance. Essential actions include:

• Removing and destroying heavily infested or dead wood to reduce the local population.
• Sealing any mechanical injuries or cracks on tree trunks with appropriate wound dressing.
• Maintaining tree health through proper irrigation and nutrition to prevent them from becoming attractive to beetles.
• Implementing regular site inspections to detect early signs of larvae activity.