The public are being urged to be vigilant for any sightings of oak processionary moth caterpillars, a tree pest which can strip oak trees of their foliage and leave them susceptible to disease.
The caterpillars - predominantly found in South East England - descend down oak trees in head-to-tail processionary form, occasionally taking the form of an arrow shape, earning them their name. They feed on the leaves as they migrate causing the leaves to sometimes drop off which negatively impacts their growth. This can weaken the tree and leave it more vulnerable to other stresses, such as drought and further diseases.
The warning has been issued today by the Forestry Commission who are urging the public to report any sightings to the via the TreeAlert portal or by email to opm@forestrycommission.gov.uk.
Pretty sure that it is supposed to be DEFRA rather than DEFA.
Very good explanation of the situation here: https://www.forestresearch.gov.uk/tools-and-resources/fthr/pest-and-disease-resources/oak-processionary-moth-thaumetopoea-processionea/
