Forestry Commission identify eight-toothed spruce bark beetle

Earlier this month the Forestry Commission identified a breeding population of the eight-toothed spruce bark beetle (Ips typographus) in the UK.  This pest has the potential to inflict damage on commercial spruce forests, but also plants grown in tree nurseries and specified by landscape professionals.    

The eight-toothed spruce bark beetle is native to Europe and commonly found in the same areas where its preferred host, Picea abies, grows.  Whilst the beetle is no stranger to British shores (it has previously been intercepted at British ports and caught in a paper mill) the discovery earlier this month is the first time it has been discovered in the wider environment as a viable breeding population.

Route of entry

Whilst the eight-toothed spruce bark beetle is capable of flying up to 4km, the primary method of movement over large distances (and the likely pathway taken most recently) is via transport either in the form of live plants or in packaging made from plant material.

The UK and Ireland have protected zone status, meaning phytosanitary measures in the form of a plant passport - which confirms material is sourced from areas known to be free from the beetle - have been imposed on imported living material to prevent entry to this pest.  Non-living plant material must undergo preventative measures such as removal of bark, heat treatment or chemical treatment to minimise the potential for entry.   

Damage

The eight-toothed bark beetle is believed to be the most serious pest of spruce in Europe.  Whilst it prefers weakened, stressed or felled trees, large concentrations of the pest are can kill healthy specimens.  Research suggests smaller spruce trees less than 15 years old (including domestic Christmas trees) are too small to be susceptible and unlikely to be affected, however. 

Identification

Adults are in the region of 4 – 5.5mm long in a black/brown colour.  Adults hibernate in forest litter during winter, and burrow into host trees to lay eggs when conditions are more favourable in spring, summer and autumn. 

Suggested action

BALI members are urged to make a note of the description above and use the online Forestry Commission’s Tree Alert portal if they identify living or dead material they believe to be infected.  

Image courtesy of Forestry Commission