Fera Provides Greater Protection for Sweet Chestnut Trees in England, in Partnership with Defra


Fera Provides Greater Protection for Sweet Chestnut Trees in England, in Partnership with Defra

Credit: Dr Chris Malumphy, Fera Science Ltd. Image Credit: Dr Chris Malumphy, Fera Science Ltd.

Fera is proudly stepping up the fight against an invasive tree pest of sweet chestnut trees, the Oriental Chestnut Gall Wasp, as announced by the UK’s Chief Plant Health Officer.

Working with the Department for the Environment Food and Rural Affairs (Defra), Fera will sensitively control the release of a biological control agent, a parasitoid wasp called Torymus sinensis, to help reduce the spread of Oriental Chestnut Gall Wasp in England in the efforts to protect the health of sweet chestnut trees.

The control agent release has been approved following extensive research, a thorough risk assessment, and careful testing, commissioned and conducted by Fera in partnership with Defra, to ensure the safe, controlled release of the parasitoid in the UK.

Senior Scientist at Fera Science Ltd Neil Audsley said:

Following an extensive programme of research and thorough risk assessment, we are now able to release a biological control 

agent to reduce the population of Oriental Chestnut Gall Wasp. Biological control is the safest and most effective means to manage pests such as Oriental Chestnut Gall Wasp. This strategy has been successfully used in countries across Europe and will directly contribute to improving the health of sweet chestnut trees in England.

The Oriental Chestnut Gall Wasp was first found in England in 2015. The wasp causes damage through galls on the buds and leaves of the sweet chestnut tree. In high numbers, the gall wasp can weaken sweet chestnut trees and make them more vulnerable to other pests and diseases, including Sweet Chestnut Blight.

The biological control agent, Torymus sinensis, is already present naturally in England but in very low numbers and further releases of the parasitoid will enable the tree population to increase to a level that will effectively control Oriental Chestnut Gall Wasp. This method of biological control is used successfully in many countries across Europe.

Fera will follow the release with a programme of monitoring for the next 10 years to carefully regulate the biological control, having gained governmental approval after robust scientific review, including by the Advisory Committee on Releases to the Environment and a public consultation.

Chief Plant Health Officer Nicola Spence at Defra said:

Threats to sweet chestnut trees have increased as a result of tree pests and diseases such as Oriental Chestnut Gall Wasp and Sweet Chestnut Blight. The release of this biological control agent represents a huge step towards protecting the health of sweet chestnut trees and will further enhance the resilience of our treescape.”

The release of Torymus sinensis is part of the government’s long-term strategic response to managing threats from tree pest and diseases to achieve the goals of the Tree Health Resilience Strategy (2018). Working in partnership with world leading scientists and researchers, Fera, in partnership with Defra will continue to protect England’s sweet chestnut trees from existing and emerging threats.


Copyright © 2024 Fera Science Limited (“Fera”). All rights reserved.

Registered Office: York BioTech Campus, Sand Hutton, York, YO41 1LZ. Registered in England & Wales, No 9413107. VAT Registration ID: GB 456401013
For further information about how Fera uses any personal data collected from you, please see our Privacy Notice at www.fera.co.uk/privacy-policy.