Feb 03 2022

Unwelcome visitors at Brede High Woods

Only just over a month into the New Year and we’re already dealing with another potential controlled pest at Brede High Woods, East Sussex, in the form of the 8-toothed European spruce bark beetle (Ips typographus), which – though tiny- you will agree sounds like it could wreak some havoc. Unfortunately, it has been found in the woods to the north of the site and has prompted premature felling of all of our spruce to avoid an infestation.

 

What is it?

The larger eight-toothed European spruce bark beetle (Ips typographus) is considered a serious pest on spruce in Europe and has recently been found in the wider environment in England as part of routine plant health surveillance activity.

The beetle is mainly a secondary pest, preferring stressed or weakened trees. However, under the right environmental conditions, beetle numbers can increase enough to result in attacks on living trees.

If left uncontrolled, the beetle, in association with pathogenic fungi (particularly the blue stain fungus Endoconidiophora polonica), has the potential to cause significant damage to Britain’s spruce-based forestry and timber industries.

Adult beetles are dormant and hibernate over winter under the bark of trees, logs and leaf litter. They then re-emerge in spring, when the temperature rises above 20°C. The beetle prefers stressed or weakened trees e.g. windblown, damaged and recently felled spruce trees, where, under the right environmental conditions, beetle numbers can increase. Inspection of trees in this category should be a priority.

Also look for standing individual and groups of dead trees. This arises when the beetles ‘mass attack’ trees, overcoming the trees’ usual defences by a combination of large numbers and blue stain fungus carried by adult beetles. Under the right environmental conditions, this phase can lead to extensive tree deaths.

Adult females lay eggs along a linear gallery system from which larval galleries radiate, becoming wider as the larvae grow. The pattern shows in the bark and in the surface of the wood, and is unique to Ips typographus. This symptom should be looked for in any dead trees, whether standing or fallen.

 

(Source: https://www.gov.uk/guidance/eight-toothed-european-spruce-bark-beetle-ips-typographus, 2022)

 

Thank you to Dave Bonsall, Site Manager for East Sussex and Kent, for this information. 

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