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Oak processionary moth

Nests of the oak processionary moth discovered - what to do?

From mid-May until August, caterpillars or caterpillar nests of the oak processionary moth are likely to appear in the entire city area. It can be assumed that a large proportion of the oak trees in the city area will be infested. To report caterpillars or caterpillar nests of the oak processionary moth on trees in the area of the city of Bocholt, please use the online reporting form.

Note: On public land the municipality is responsible for the removal of nests, on private land the owner!

Below you will find a digital map in which all already reported or known infestation sites in the city area are marked. The online reporting procedure and the overview map were developed by the district of Borken and the city of Bocholt and made available to the municipalities and communities belonging to the district.

The oak processionary moth

Map: Reported nests in the district

On the following map you can see where nests of the oak processionary moth have been reported in the district of Borken:

This map is linked from the GeoData Portal of the district of Borken. When retrieved, usage data may be transmitted to third parties. If you agree to this, click here. (For details see privacy policy)

Dangers due to oak processionary moth

Skin rash EPS
Contact with the stinging hairs triggers skin rashes and itching

The stinging hairs of the caterpillars, which contain a nettle toxin, can cause considerable health problems for humans and animals.

Contact with the almost invisible hairs causes skin rashes, burning and itching. More rarely, more severe reactions such as respiratory irritation, conjunctivitis or fever occur.

If allergic symptoms occur, the attending doctor or dermatologist should be consulted!

Prevention through biological means

From mid-May onwards, the city of Bocholt will have the urban oak stands treated with a microbiological biocide from the ground or from a cherry picker as a precautionary measure. The agent is considered harmless to humans and animals when used properly. The active ingredient is based on a protein produced by the bacterium Bacillus thuringiensis.

Due to its selective effect, it is particularly gentle on beneficial insects and not dangerous to bees. The agent inhibits the development of the caterpillars so that no nettle hairs are formed in the first place. The spraying measures are carried out at the end of April / beginning of May by the Entsorgungs- und Servicebetrieb Bocholt (ESB) and an externally contracted company.

Due to these measures, a strong decrease in the population could be observed in the past years.

City relies on titmice as a supplement

Since last year, the administration in Bocholt has been trying out a new method in addition to the usual precautionary measures: titmice are to help contain the emergence of the oak processionary moth caterpillars in a natural way.

The idea comes from the Netherlands. There, fewer caterpillar infestations have been observed in streets with oak trees where many titmice nest.

Nesting boxes for titmice were hung at four selected locations in the outdoor area. During the breeding and nesting season, the birds also use the caterpillars of the oak processionary moth as food. However, only as long as it has not formed stinging hairs. In addition, reported nests on public areas are removed by the Bocholt city administration.

Frequently asked questions

Who is responsible for the control of the oak processionary moth?

This depends on where the nests occur:

  • On public areas, the city of Bocholt is responsible for removing nests.

  • On private areas, the removal of nests is the responsibility of the owners.

Are the hairs of the oak processionary moth dangerous?

The stinging hairs of the caterpillars from the third larval stage onwards contain the nettle toxin thaumetopoein (named after the scientific name of the oak processionary moth), which can trigger an immune reaction.

This manifests itself in itching, skin inflammation and occasionally in hives. Especially if the stinging hairs get into the eyes or respiratory tract, more severe reactions can occur.

Source: Nature Conservation Union (www.nabu.de)

How many trees are affected in Bocholt?

In Bocholt, around 170 hectares of outdoor areas are affected by the oak processionary moth's preferred species of English oak.

Indoors, around 2,200 oaks on public land are recorded. In addition, there are oaks on private property. The administration has budgeted 181,000 euros for the control.