Great spruce bark beetle

The great spruce bark beetle (Dendroctonus micans) is established in southern and central Scotland and is slowly extending its range northwards.

All reports of great spruce bark beetle in Scotland are from spruce trees (Picea spp).

Great spruce bark beetles tunnel into the bark of living trees to lay their eggs.

The larvae then feed and develop, forming galleries that weaken, and in some cases kill, the host tree. 

When was great spruce bark beetle discovered? 

Great spruce bark beetle was first detected in southern Scotland in 2003, having gradually expanded northwards from its establishment in England and Wales during the 1970s and 1980s.

A common pest of spruce and pine in mainland Europe, great spruce bark beetle is not native to the UK.

Trees are more likely to be infested by the great spruce bark beetle if they are already damaged or stressed. For example, spruce trees with damaged branches, or growing in droughted or waterlogged soils, are more susceptible to attack and likely to sustain worse impacts. 

Keep trees healthy, monitor them regularly, and design forests fit for the future. 

Invasive bark beetle umbrella leaflet

Invasive bark beetle poster

Prevent pests and diseases

Forest Research operates a biological control programme in which the specialist predatory beetle Rhizophagus grandis is reared in the laboratory and released at sites infested with great spruce bark beetle. 

The aim of this programme is to reduce damage where great spruce bark beetle is already present and to slow its spread into areas that remain free of the pest.

Although the programme has significantly delayed the northward expansion of great spruce bark beetle, it continues to spread, leaving a large area of spruce still at risk.

Use Tree Alert to report any suspected symptoms.

Forest Research will then review the site information and determine if it requires a site survey and/or inclusion in the Rhizophagus release programme.

Note that felling infested trees makes it harder for Rhizophagus grandis to build up sufficient populations to effectively predate the great spruce bark beetle.