Most pest problems are private: a mouse in the kitchen or wasps in the eaves. Some pests of trees and plants are different, because government treats certain outbreaks as a matter of public interest and wants sightings reported rather than handled quietly. This article summarises GOV.UK guidance on reporting a tree pest or disease and the Forest Research description of its TreeAlert service. It covers Great Britain and refers briefly to Northern Ireland, and it is general information, not plant health advice.
Why reporting matters
GOV.UK explains that notifiable tree and plant pests and diseases have the potential to cause the greatest damage. Once a report is confirmed, the authorities plot the location so that it can inform local tree and woodland managers, take preventive action to limit spread and, where possible, pursue eradication before the organism becomes established. A garden owner who treats a suspicious problem without telling anyone may therefore lose the chance of early containment. A pest controller called to a garden tree should treat unusual symptoms as something to report as well as something to treat.
Where to report in each part of the UK
GOV.UK gives different routes depending on the location:
- Trees in England, Scotland and Wales: use the TreeAlert service run by Forest Research.
- Plants in England and Wales: use the online form on the GOV.UK submission service.
- Plants in Scotland: report to SASA (Science and Advice for Scottish Agriculture).
- Commercial locations: the guidance directs reports to the Animal and Plant Health Agency (APHA) through its online plant health form.
- Northern Ireland: the guidance directs enquiries to the Department of Agriculture, Environment and Rural Affairs (DAERA).
The guidance was last updated on 3 September 2026, when an out-of-date email address was replaced with the online reporting form.
What TreeAlert asks for
Forest Research describes TreeAlert as the online tool for reporting tree pests and diseases, managed by Forest Research with funding from Defra, the Forestry Commission, Scottish Forestry and the Welsh Government. A report is made through a series of screens. The reporter provides a name, email address and level of experience; the date and location, given as a grid reference, map point or postcode; the number of affected trees and the tree type; and a description of symptoms. Photographs are requested, ideally three: the whole tree in its setting, the symptoms in context showing how they are distributed on the tree, and a close-up of the fine detail.
The pictures need to be clear enough to show what the reporter intends, in natural light or with a flash so they are not blurry or dark. Reports are processed through Forest Research’s tree health diagnostic and advisory service, and staff may contact the reporter for more information. According to Forest Research, the information supports monitoring and surveillance work, contributes to scientific research and helps protect the nation’s trees.
What not to do
- Do not assume that a stripped, discoloured or unusually dying tree is a nuisance to be dealt with privately; photograph it and report it.
- Do not rely on a general pesticide as a substitute for identification; products have legal conditions of use, as the site’s article on pest products as biocides explains.
Who receives the information
Because TreeAlert is funded by Defra, the Forestry Commission, Scottish Forestry and the Welsh Government, reports feed a shared picture across Great Britain rather than staying with one local body. Forest Research states that the information supports tree health monitoring and surveillance, contributes to ongoing scientific research and ultimately supports efforts to protect trees. For a householder, that means one photograph-led report can serve England, Scotland and Wales alike, whichever part of Great Britain the tree stands in.
Relationship to other reporting matters
Tree pests are only one category of reportable organism. The site covers others individually, including the oak processionary moth, which the Forest Research TreeAlert page lists among its popular search topics alongside acute oak decline. Each has its own guidance, so the TreeAlert report is the general entry point, not a substitute for reading the pest-specific advice.
Common questions
Do I have to give a location precisely?
TreeAlert accepts a grid reference, a point on a map or a postcode, so an exact grid reference is not compulsory.
Can I report a pest on a garden plant, not a tree?
GOV.UK gives separate routes for plants: an online form in England and Wales and SASA in Scotland.
What happens after I report?
Forest Research staff may contact the reporter, and confirmed findings are plotted and used to guide preventive action, according to the sources above.
Is TreeAlert available in Northern Ireland?
The Forest Research page does not mention Northern Ireland, and GOV.UK directs enquiries there to DAERA.
The bottom line
Suspected pests and diseases of trees and plants are reported to public bodies, not just dealt with privately. In England, Scotland and Wales, trees go through TreeAlert with clear photographs, plants go through the routes GOV.UK lists for each nation, and Northern Ireland enquiries go to DAERA. Reporting early supports containment and monitoring across the country.
Sources
- GOV.UK, “Report a tree pest or disease: overview”
- Forest Research, “TreeAlert” (forestresearch.gov.uk)