Observatree activity to the end of June 2018

Volunteer activity

Number of hours recorded: 14,971.5

Number of tree health site surveys completed: 3,729

Number of site surveys which found a pest of disease: 1,315

Number of site surveys which found a suspected Observatree priority pest or disease: 858

Priority pest and disease findings

  • Acute oak decline
  • Chalara dieback of ash
  • Dothistroma needle blight
  • European mountain ash ringspot virus
  • Great spruce bark beetle
  • Horse chestnut leaf miner
  • Oak processionary moth
  • Oriental chestnut gall wasp
  • Phytophthora austrocedri
  • Phytophthora lateralis
  • Sirococcus tsugae

Other key findings

  • Sirococcus conigenus
  • Dutch elm disease
  • Phytophthora alni
  • Oak powdery mildew

Tree Alert reports submitted between the start of October 2017 to the end of June 2018

Tree Alert enquiries by country (total 864)

Top 5 host tree species in order:



Sweet chestnut



Top pathogen reported: Chalara    

Top pest reported: Oak processionary moth