What are oriental chestnut gall wasps?
Oriental chestnut gall wasps are small insects (2.5-3mm) with black bodies and orange brown legs. Originating from Asia, this species arrived in Europe in 2002 and was first recorded in the UK in 2015 in a woodland in Kent and later in the same year in Hertfordshire. In these cases infested trees were destroyed in an attempt to stop the insect becoming established in the UK. In 2016 however, the gall wasp was found in several areas of London extending into Surrey. In 2017 this spread has continued and it is becoming fairly widespread in south east England.
If you suspect a case of oriental chestnut gall wasp, please report via TreeAlert.