The Oak Processionary Moth Caterpillar – Be Alert!

The Forestry Commission is urging landscapers, grounds maintenance contractors and tree surgeons to be aware of the Oak Processionary Moth caterpillar which has been found in increasing numbers across the South East of England in recent years.  

The caterpillars (larvae) of oak processionary moth (OPM) are pests of oak trees, and a hazard to human and animal health. OPM was first accidentally introduced to England in 2005 and is subject to a government-led programme of survey and control to minimise its population, spread and impacts.

The Oak Processionary Moth lays its eggs on Oak trees and when the larvae are ready to leave the cocoon they immediately feed on the leaves of the tree, stripping it back until all that is left is bare branch. The caterpillars are highly toxic to humans and can trigger asthma attacks, fevers and severe skin rashes. The greatest risk period is May to July when the hairs have developed on the caterpillars and not only cause harm by sticking to clothing and skin on contact but can actually be blown by the wind. The hairs contain a substance which can cause itching skin rashes, eye irritations and occasionally sore throats and breathing difficulties in people and animals.As well as landscapers, grounds maintenance contractors, tree surgeons and forestry workers, farmers and pet owners should be alert.

The Forestry Commission has advice on their website on how to minimise the spread of this pest, how to report a sighting and precautions for protecting workers who may be at risk. To find out more go to

For more information about planning and planting woodland or trees contact our team or go to our Tree Planting Page.