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Joining forces in the fight against oak processionary moths

13/2012, 19.03.2012

Joint press release of the Julius Kühn Institute (JKI) and the Federal Institute for Risk Assessment (BfR)

The processionary moth (lat. Thaumetopoea processionea) continues its spread through Germany. In forests, urban green zones such as parks, playgrounds and alley trees, the moth is on the increase everywhere. The caterpillars of the thermophile butterfly do not only cause damage to oaks. In addition, they have stinging hair which can lead to skin and eye irritations, breathing difficulties and even allergic reactions when they come into contact with humans. Experts rate the potential health damage of the oak parasite very high. Not only from the viewpoint of forest protection, therefore, these insects must be controlled. The Julius Kühn Institute (JKI) and the Federal Institute for Risk Assessment (BfR) organised a conference for representatives of the competent federal and state authorities as well as experts from the worlds of theoretical and applied science. The conference took place in Berlin from 6 to 7 March 2012.

The starting point of the discussion was, apart from the damage caused to oak trees, the mounting reports of health problems of forestry workers and gardeners and even local residents and people going for a stroll. It became clear that the stinging hair which the caterpillar develops from its third chrysalis stage poses a direct health risk which, due to its persistence in the affected areas, lasts for a long time.

For reasons of health as well as forest protection, the parasite must be combated both in forests and urban green zones. This is a point on which there was unanimous agreement among the assembled experts. “The oak processionary moth is a wanderer between two worlds, however. On the one hand, it is a pest which must, for example, be combated with insecticides in forests as a matter of principle and in accordance with plant protection laws”, explains Dr. Georg F. Backhaus, President of the Julius Kühn Institute. On the other hand, it causes damage to human health. In such cases, biocide regulations apply”, Backhaus continues.

Professor Dr. Dr. Andreas Hensel from the Federal Institute for Risk Assessment aptly summarised the situation:  “What is worse, the effects of the stinging hair of the oak processionary moth or the side effects of insecticide application?” Here those responsible must weight up the health risks posed by the pest versus the side effects that can result from the use of insecticides.

One problem confronting the authorities is that to date only a few scientifically founded data collections exist on the effects of the stinging hair as presented during the expert talk by doctors of the District Administrations of Teltow-Fläming in Brandenburg and Kleve in North Rhine-Westphalia.

It emerged that the measures to be taken to fight the pest must be adapted to specific local conditions. The spectrum of measures covers everything from declaring off-limits affected areas to the use of insecticides, for example from the air, and local measures such as specialists wearing complete protective clothing and masks sucking caterpillar nests and hair off individual trees. The conference conveys the message that all involved authorities must work on a joint strategy in order to provide solutions to protect residents and to preserve urban green zones and oak forests.

A publication documenting the findings of the conference will appear. Users will be able to view the various papers on the web pages of the BfR and the JKI.

An information sheet for the general public on oak processionary moths (in german only) can be requested from the JKI press centre or downloaded as a PDF from the following URL:


Bundesinstitut für Risikobewertung (BfR)
Max-Dohrn-Str. 8-10, 10589 Berlin, Germany
Tel: 030/184124300

Julius Kühn-Institut, Bundesforschungsinstitut für Kulturpflanzen
Messeweg 11-12, 38104 Braunschweig, Germany
Tel: 0531/299-3207


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