The Plant Health Service has intercepted an increasing number of cases of Oak Processionary Moth (OPM) caterpillars on trees imported from the continent.

On Monday 15 July, new legislation came into force to strengthen existing protections. Find out more at

At risk are ‘larger’ oak trees (defined in this case as those over 8cm in girth at 1.2m above the root collar) that have been imported from Germany or the Netherlands since September 2018. Defra has requested that, in the public interest, the LI reinforce to our members the need to inspect any at-risk trees and report any findings to TreeAlert as a matter of urgency.

The Plant Health Service (APHA and Forestry Commission) is taking swift action to eradicate any findings. The potential environmental effects of this pest spreading are enormous, and we urge members to:

  • respond to any requests for information from Plant Health Service officials as fully and quickly as possible
  • in cases where they have planted at-risk trees, to check for OPM and report any findings to TreeAlert

OPM nests and caterpillars can pose risk to human health. If you suspect OPM, do not attempt to destroy or move infected material yourself. For more on how to identify OPM, visit the Forest Research website.

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