UK Government Warns Public Not to Touch Oak Processionary Moth Caterpillars

The UK government has issued a public health warning ahead of the oak processionary moth (OPM) peak season, urging people to "stay vigilant" and avoid any contact with the caterpillars or their nests. Warm spring weather is expected to accelerate the insects' development, potentially leading to higher infestation levels across oak trees, particularly in the South‑West, South‑East, Derbyshire and Dorset.

OPM caterpillars can cause itchy rashes, eye and throat irritation, and in severe cases allergic reactions requiring medical help. The advisory advises anyone who spots the pest to report it via the TreeAlert portal or email the Forestry Commission, and stresses that control work should be carried out only by professional contractors. The Royal Horticultural Society also notes the risks of the irritating hairs and recommends professional removal.

Officials emphasize that the insects feed exclusively on oak foliage, threatening tree health and making them more vulnerable to disease. The guidance aims to protect both public health and the iconic oak trees that are considered under threat.