Forest and wood pests electronic identification and monitoring system

Isotomus speciosus

Longhorn beetle Isotomus speciosus

Fuzáč Isotomus speciosus is a longhorn beetle developing in the dry wood of deciduous trees, with a preference for hornbeam (Carpinus betulus) but also occurring in oak, chestnut, beech, elm, and maple. Females often lay their eggs repeatedly in the same wood, leading to complete internal destruction over time. Larvae first feed in the outer layers and later burrow deep into the heartwood. The development lasts at least two years and is influenced by wood moisture. Adults are active from June to August and can be seen both during the day and at night. The species is widely distributed across Europe and the Caucasus, although it is becoming rare in parts of Central Europe due to habitat loss. The damage reduces the structural and aesthetic value of standing or stored hardwood.

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On exposed wood, oval exit holes and deep larval galleries extending into the heartwood are visible.

Tree Species: Elm, Beech, Oak, Maple

Part of a plant- attacked: Tree trunk, Branch

Pest significance: Not 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: Individually - one place

Prevalence in Europe: Rare

Damaged products: Firewood, Lumber, boards and prisms, Stored timber logs (dried wood)

Roundwood size: Branches and twigs, Diameter from 10 up to 50 cm, Diameter up to 10 cm

Wood discoloration: No

Exit holes: Oval

Pest subcategory: Wood-boring insect

Foto: Ján Kollár

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