Cerambyx welensii

Longhorn beetle Cerambyx welensii

Cerambyx welensii is a large longhorn beetle in the family Cerambycidae, measuring 25–58 mm in length. It is widespread in Southern Europe, North Africa, and the Near East, inhabiting oak forests and mixed woodlands. The species mainly feeds on oak species such as cork oak (Quercus suber) and holm oak (Quercus ilex), but it can also develop on other broadleaf trees like Juglans, Fraxinus, and Platanus. Larvae are xylophagous, boring deep galleries into trunks and branches of living trees, weakening their structural integrity and vitality.

The life cycle spans three years, with larvae causing significant damage as they grow. Adults are active from mid-May to late July. Infestations often lead to branch dieback and bark cracking, making trees more vulnerable to pathogens and secondary pests, and reducing their aesthetic value in forested and urban settings.

Map

Symptom

More info

More Photograps

Affected trees show deep larval galleries in the trunk and branches. Bark may crack, and large oval exit holes are often visible. The wood appears structurally weakened and roughened. Frass can be seen at the base of the trunk.

Tree Species: Oak, Ash, Walnut

Part of a plant- attacked: Tree trunk, Branch

Pest significance: Harmful

Pest Category: Insects

Invasive Species: No

Present in EU: Yes

Pest group: Insect

Affected part of wood: Heartwood, Sapwood

Depth of damages: Bark, More than 5 cm depth, Under bark only, Up to 0,5 cm depth, Up to 2 cm depth, Up to 5 cm depth

The extent of damage: Lokally

Prevalence in Europe: Common

Damaged products: Firewood, Fresh timber logs (water still in the sapwood), Furniture, Lumber, boards and prisms