During April/May, essential insecticide spraying takes place in Richmond Park, Bushy Park and Greenwich Park against the invasive insect pest Oak Processionary Moth. During the spraying operation areas of the park may be temporarily closed to the public or marshals will be in place to direct people away from the vicinity. Please follow any instructions on signage or given by the marshals, to ensure a safe and enjoyable visit.
What is the Oak Processionary Moth?
The Oak Processionary Moth is an invasive insect pest of Oak trees originating from central and southern Europe and first found in the UK in 2006.
Why are they considered a problem?
The hairs of the caterpillars carry a toxin which can be a threat to human and animal health, causing persistent itchy skin rashes, eye and throat irritation and sometimes breathing difficulties in people and animals.
In high numbers the caterpillars can also cause extensive defoliation of oak trees leaving them vulnerable to other pests and diseases, drought and climate change.
During this time the park is surveyed for nests which will then be removed by specialist operatives using protective clothing and equipment. Although every effort is made to control the moth, the toxic hairs may still be present.
When are the caterpillars active?
The eggs of the moth hatch on oak trees in April. The caterpillars then develop through six stages during May, June and July, before retreating in to webbed nests from which the adult moths emerge in mid August.
The optimum time to carry out insecticide spraying is during April and early May when the caterpillars are very small. The optimum time to manually remove the nests is from July to the beginning of August, when all the older caterpillars have retreated in to permanent nests which can be removed before the moths emerge.
Summer is the time of year when the caterpillars of this invasive Moth are on the move and may be found low on the trunk and branches of oak trees, where they may also form webbed nests.
How is The Royal Parks dealing with the problem?
The Royal Parks adopts a rigorous approach to the management of Oak Processionary Moth. In 2022 we will be carrying out a limited and carefully targeted insecticide spraying programme in April and May on some oak trees in the affected parks. This will be followed by systematic surveying of the parks and manual nest removal of caterpillar nests by specialist teams at the optimum time from the beginning of July to the middle of August.
In 2022 spraying will take place in Richmond, Bushy and Greenwich Parks only.
The government approach to Oak Processionary Moth is to control, not eradicate, the pest in the established outbreak zone. The rigorous approach that The Royal Parks adopts towards the management of Oak Processionary Moth ensures we are able to control the problem and ensure the safety of park visitors and all the people and animals who use the parks as far as is reasonably practical.
Is the insecticide harmful to people and animals?
The insecticide used is classed as non-hazardous but may be a temporary irritant during application. During the spraying operation areas of the parks may be temporarily closed to the public, or marshals will be in place to direct people away from the vicinity. Any instructions on signage or given by the marshals should be followed, to ensure a safe and enjoyable visit.
What if I spot Oak Processionary Moth caterpillars or their nests?
If you come across the caterpillars or their webbed nests please do not touch them and keep children and pets away.
It is important that you:
- DO NOT touch or approach the caterpillars or nests
- DO NOT try to deal with them yourself. This requires specialist expertise and careful timing
- WARN children not to touch or approach caterpillars or nests
- KEEP pets away
Please report sightings to the appropriate park office: Richmond (0300 061 2250) / Bushy (0300 061 2200) / Greenwich (0300 061 2380)
If you (or your child) have already come into contact with an Oak Processionary Moth nest (or caterpillars) please seek medical attention. Similarly, if your dog has rolled in/picked up an Oak Processionary Moth nest on the ground please seek advice from a qualified veterinarian as soon as possible.
