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Urocerus gigas

Greater horntail wasp

Description

The Urocerus gigas is a large wasp species, with males ranging from 15 to 30 mm in length, and females being even longer. Their bodies are elongated and yellow in color. Females have a highly visible ovipositor. These wasps are active from June to August. Females lay several hundred eggs directly into the wood, and the larvae bore long, sinuous tunnels deep into the wood. The development process is slow and can take two to three years or even longer. Adults emerge from typical circular exit holes. The Urocerus gigas typically damages conifers that have been previously injured by fire, weakened by insects or pathogens, or wounded by harvesting. It is considered one of the most important technical pests of coniferous trees, particularly spruce and fir. Additionally, symbiotic fungi associated with U. gigas can also cause technical damage to the wood.

Symptom

A large wasp-like Hymenoptera perched on a tree. Round exit holes.

Tree Species: Pine, Douglas Fir, Fir, Spruce, Larch

Part of a plant- attacked: Tree trunk

Pest significance: Harmful

Pest Category: Insects

Invasive Species: No

Present in EU: Yes

Last observations

There are a total of 9 observations of the species in the system

Urocerus gigasGreater horntail wasp
Lenka Zupkova
Number of votes: 0
Published: 20.8.2025

Urocerus gigasGreater horntail wasp
misko
Number of votes: 0
Published: 16.8.2025

Urocerus gigasGreater horntail wasp
Michal Pánis
Number of votes: 0
Published: 15.7.2024

Urocerus gigasGreater horntail wasp
Michal Pánis
Number of votes: 0
Published: 15.7.2024

Urocerus gigasGreater horntail wasp
Michal Pánis
Number of votes: 0
Published: 15.7.2024