Oak Processionary Moth Caterpillars - a noxious pest

Caterpillars of the OPM

Caterpillars of the Oak Processionary Moth (OPM) doing their “thing”! - Photo by Henry Kuppen

The oak processionary moth (OPM), which hatches in July and August, was first discovered on the Common in July, 2019. The caterpillars of this little blighter, which are covered with up to 63,000 pointed defensive bristles, are a noxious pest, and are a hazard to the health of oak trees, people and animals.

Contact with the bristles can cause itching, skin rashes and, less commonly, sore throats, breathing difficulties and eye problems, and this can happen if people or animals touch the caterpillars or their nests, or if the bristles are blown into contact by the wind. The greatest risk period is May to July, but the bristles - which can be active for up to five years - can be present on old nests (which may have fallen on to the ground) and could be blown or touched at any time of year.

New silken white OPM nests and trails

New silken white OPM nests and trails, which can be anywhere on an oak tree from ground level right up as far as the highest branches - Source https://www.forestresearch.gov.uk/

Identifying OPM caterpillars and their nests: The caterpillars live almost exclusively in oak trees, and move in nose-to-tail processions in oak trees or on the ground, hence their name, and build white, silken webbing trails and nests - usually dome or teardrop-shaped - on oak trunks and branches (but not among leaves), though the nests soon become discoloured. The damage which their feeding does is quite distinctive and noticeable, because the caterpillars tend to leave the leaves skeletonised, with only the main veins remaining.

So if you see any oak tree on the Common with these nests or with a strange infestation of caterpillars, and especially if you discover any fallen nests, please try to keep dogs and children away, don't touch them yourself, and inform the Curators immediately. But first, please, CHECK that they're in or near an oak tree - OPM caterpillars usually only attack other trees if they run out of oak leaves to eat!

The Common is not a nature reserve but it, and the adjacent Covert Way Local Nature Reserve and the open land belonging to Hadley Wood Golf Club, are havens for wildlife. Its importance in this respect is increased by its location on the urban fringe, where pressures on wildlife are considerable.

Latest News

Although the Trust does not have a 'News' section on our website we aim to provide occasional updates of recent activity and future plans.

'Bund'

Users of the Common may have seen notices placed by Enfield Council regarding the planned introduction of a drainage 'bund' on the Common to the south east of Parkgate Avenue. The Trust supports the project as it will improve a very wet and therefore inaccessible part of the Common and hopefully stop homes being flooded after extreme rainfall. The ‘bund’ will be a relatively small area with raised sides into which excess rainfall will flow and then gradually drain through the usual system. It is expected that work will start in the next few months and be complete in the spring. It should not take long to construct but exact dates are not yet known.

Paths

As regular users of the Common will doubtless have noticed, brambles are spreading across many of the smaller and less used paths. Our Volunteers (see ‘Vacancies Corner’ on the website if you are interested in volunteering) try to keep the paths clear however the wet summer has meant the brambles are winning just now. Please feel free to join us on a Tuesday or Thursday morning to keep trimming.

Bakers Hill & carpark

The surface of the car park at Bakers Hill has deteriorated over recent years, particularly the entrance. Tarmac has recently been laid at the entrance and hollows filled elsewhere in the carpark. This has been done in an effort to increase use of the car park and reduce parking on Bakers Hill. Parking on Bakers Hill narrows the road inappropriately (large trucks need access to the railway and utilities running across the Common) and damages the Common. In due course, now the carpark surface has been improved, bollards will be placed at the unofficial lay-bys along Bakers Hill to stop parking.

Tree work

We have recently undertaken a review with our arboriculture advisor and noted trees which need or may need attention in the future. Trees have been marked accordingly to help future identification. We will only reduce or remove trees if or when safety becomes an issue for users of the Common.

Funds

As users of the Common will realise, it costs a substantial amount annually to maintain the Common as a safe and pleasant environment which is open to all. Work, as outlined above, costs a great deal. The Trust urges those who use and enjoy the Common to contribute whatever they can in an effort to support the Trust. Membership is open to all - see the Membership tab on the website, and as a registered charity the Trust welcomes donations, small and large!

Vacancies corner

  1. Woodlands volunteer - we are looking for someone with expertise on woodlands in general to join either as a volunteer or, possibly, as a trustee. Please contact treasurer@mhctrust.org.uk for more details.