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Oak pinhole borer (Platypus cylindrus)

PLATYPUS CYLINDRUS . Boreholes in oak heartwood caused by pin - hole borers . Location: Wield , Hampshire , England .Oak pinhole borer (Platypus cylindrus) is a pest mostly of oak trees, although it will also attack other hardwoods.

Its larvae (grubs) can bore deep into the heartwood of stressed oak trees, degrading the timber's appearance and therefore its value. It is the only borer which, in the absence of fungal decay, will bore into the heartwood of oak.

Oak pinhole borer appears to establish only in trees which are severely stressed or already dead, and is not itself responsible for killing trees. As its name suggests, it prefers oak, but will readily attack other hardwoods, notably sweet chestnut and beech, the latter particularly when some fissuring of the bark has occurred. It has also been known to breed in ash, elm and walnut.

Concerns about the presence of the oak pinhole borer in oak logs imported from continental Europe have been raised with our Cross-Border Plant Health Service.

Oak pinhole borer used to be regarded as rare in Great Britain. However, populations grew in the south and south-east after the 1987 gales, when it took advantage of the sudden glut of suitable breeding material in the form of dead and weakened oak trees. Numbers have never returned to pre-1987 levels, and it continues to be a problem. This might be a consequence of a continuing supply of breeding material in the form of weakened oaks suffering from oak dieback and decline.

A similar situation now exists in continental Europe following the severe gales of winter 1999, and British buyers are reporting damage to oak logs bought in from there.

Life cycle

Adults usually emerge from June to September from larvae which might have been present in the log for up to three years. Adult beetles are 6-8mm long, rather rectangular in shape, and are pitchy-brown to almost black in colour.

The females lay eggs at intervals throughout their 2-3-year lives, and larvae emerge from the eggs between two to six weeks later.

Adult beetles and larvae both bore through the wood.

Control

Oak pinhole borer is not on the quarantine list because it is already present in the UK, and it is not a pest of standing, healthy trees. There are, therefore, no quarantine controls against it, and there are no treatments available which will provide protection.

There is no requirement to report sightings of oak pinhole borer.

Management

Our Forest Research agency pages on oak pinhole borer have further information and advice on ways in which timber growers and sawmillers can minimise the risk to their timber from oak pinhole borer.

We strongly recommend that anyone buying oak logs from areas where the beetle is known to occur specifies wood which is free from signs of wood borer damage.

 

Last updated: 9th May 2018