The Forestry Commission has told HW that it is considering requesting an official pest risk analysis into a new and potentially highly damaging threat to the UK's pine trees.
Studies show the pine processionary moth (PPM) has spread from its native southern Mediterranean to northern Europe where colonies have established in Paris, Brittany and Strasbourg. Experts warn that is likely to arrive in the UK.
The pest can cause total defoliation in its hosts, which include Pinus pinea and Pinus halapensis, weakening the tree against other pests and diseases and in many cases being a direct cause of death.
Like its relation oak processionary moth (OPM), already an established UK resident, the caterpillar stages of the pest's lifecycle pose a serious risk to human and animal health as well as to that of the tree in which it develops. The larvae are covered in tiny toxic hairs which can cause skin rashes, respiratory discomfort and in extreme cases anaphylaxis and sight loss.
Unlike OPM, the PPM's larval stages take place during the winter months making their survival dependent on milder weather and researchers believe its spread is linked to climate change increasing average winter temperatures in northern Europe.
In a statement issued to HW, the Forestry Commission said suitable pine woods and climate in southern Britain would make the establishment of a breeding PPM population possible. But because it was not listed as a national plant threat there was no requirement for UK-bound plants to be specifically inspected for the pest.
It stated: "We are considering commissioning a formal pest risk analysis with a view to consulting the public and if appropriate agreeing with others in the UK Plant Health Service to request the EU to approve tighter protection against the risk of PPM entering the UK. Such measures could include requiring traders moving live plants to the UK to inspect the consignments specifically for PPM."
The fact that PPM pupates in the soil would mean that for any new protection measures to be effective the tree roots would also need to be inspected.
Meanwhile the commission also revealed the west London OPM outbreak area has expanded this year to include parts of Kensington & Chelsea and Wandsworth boroughs, Wimbledon Common and Bishops Park and Hurlingham Park in Hammersmith & Fulham.
Commission plant health service head Dr John Morgan said: "Natural spread of this pest in west London is inevitable, and although we can't achieve complete containment, we believe this natural dispersal can be slowed."
No new outbreaks have been recorded and eradication would continue in Pangbourne, he added.
See also our full report - Pine processionary moth alert
"I have said for a long time that this is the one we need to be on guard for. It can ultimately kill pines pretty quickly.
"Like OPM this will come in on nursey stock and as soon as we find it those trees need to be destroyed. It's no good messing around with nest removal.
"If it arrives, it will be a real problem for our landscape."
Tony Kirkham, arboretum head, Kew Gardens.