Trade: Be vigilant for signs of tree pests and diseases

Trade: Be vigilant for signs of tree pests and diseases

News - 05 July 2018

This week, BALI Chief Executive Wayne Grills was alerted by the government’s Department for Environment, Food and Rural Affairs to communicate out to members a new national measures notice, calling for those working in a landscaping capacity to be vigilant for Oak Processionary Moth. BALI would urge all members to read through the following notice in detail.

Trade: Be vigilant for signs of tree pests and diseases

The plant health service recently rapidly dealt with a finding of Oak Processionary Moth on imported trees thanks to observations from the trade. The case highlights the need for continued vigilance to help protect the UK’s trees and forests against pests and diseases.

Oak Processionary Moth is an established pest in parts of London and surrounding areas, however the rest of the country is designated as a Protected Zone (PZ). OPM caterpillars can cause damage to oak trees and can pose some risks to human and animal health. The plant health service has controls in place to limit the spread of OPM and prevent new introductions. As a grower, importer or trader, there are steps you can take to help reduce the risk.

The paperwork

All oak moving into and within the PZ requires a plant passport regardless of the size of the consignment, and you must retain this document for at least a year. Outside the PZ, plants passports are still required if imported trees are intended for further propagation or growing on. We advise that you inspect this paperwork thoroughly and carry out careful sourcing to encourage best practice within the supply chain and improve traceability. Working in the trade, it is important to perform visual checks of your material and to report any suspicious signs of pests or diseases to a Plant Health Inspector as soon as possible.

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

Check, check and check again 

Dr Anna Brown, Head of Tree Health & Contingency Planning, Forestry Commission England, said: “Those of us involved in importing or trading plants cannot afford to lower our guard against exotic pests and diseases such as OPM. There is a lot we can do such as buying British, only buying stock from reputable, responsible suppliers and quarantining imported plants.

“Inspect, inspect and inspect again – we can’t check imported plants too often for signs of trouble. Don’t presume that because your supplier found no evidence of a pest or disease that you won’t either. You might spot something that they have missed.”

Tackling threats to plant health is not just a matter for government. By working in partnership we can help to protect the industry and our environment for years to come.


• To report sightings of pests and diseases, use the Forestry Commission’s Tree Alert app

• For more on OPM, visit

• For guidance on importing trees and plants to England and Wales from the EU visit

• To find out more about plant health Protected Zones visit

• To find out how the government will work with others to protect England’s tree population from pest and disease threats, see the Tree Health Resilience Strategy

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