Oriental Chestnut Gall Wasp

The Oriental Chestnut Gall Wasp has been found in Farningham Woods, near Swanley in Kent.  This pest’s larvae causes unusual green or rose coloured growths (or galls) to form on sweet chestnut leaves.  These galls weaken the trees and make them susceptible to diseases.  They can also affect nut and timber production!

Although these Oriental Chestnut Gall Wasps are harmful to your trees, they are no risk to people or animals! They do not bite or sting!  Also, they only affect the Sweet Chestnut Trees (Castanea family), and do not affect Horse Chestnut Trees (Aesculus family).

The Forestry Commission has been working with the government to assess the extent of the outbreak as quickly as possible, and to fell the most affected trees in the woods before the adult wasps emerge to lay eggs and spread the outbreak further afield.  Don’t worry though, all trees felled will quickly regrow from the stumps!


  • DO NOT take any plant material, including leaves, twigs, branches, bark and sticks, out of the woodland when visiting, because this could spread the pest;
  • DO keep an eye out for galls in Sweet Chestnut Trees anywhere;
  • DO report them to the Forestry Commission, including cases in your own garden;
  • CHECK that they are definitely Sweet Chestnut Trees, or give JJ&B Treecare a call and we can come and identify the tree for you!


Contact JJ&B Treecare Ltd if you have any concerns for the welfare of your Sweet Chestnut Trees…

Or for more information on Oriental Chestnut Gall Wasps, please visit this page for the Forestry Commission