Fighting oak processionary moth: how to get rid of it successfully

The oak processionary moth damages oak and causes allergic reactions in humans. We show how it can be successfully combated and removed.

It actually looks very cute, like the fluffy brown caterpillars of the oak processionary moth (Thaumetopoea processionea L.) run one behind the other in a long row to absorb the leaves of our oaks - you almost want to stroke the towering stinging hairs gently. Unfortunately, however, the softly haired larva of the oak processionary moth is serious to be taken pest, which also harms humans and animals with its allergy-triggering stinging hairs can. Everything on the subject Rash from the oak processionary moth You will find here.

Here you can find out how to recognize caterpillars and moths of the oak processionary moth (also known as "EPS" for short) and how to prevent them. You will also find all information on the development, distribution and harmful effects of the spinner caterpillars. For the sake of your health, it is better to leave the control to a specialist.

Distribution and food of the oak processionary moth

The warmth-loving oak processionary moth has been on the advance in Germany since around 1990. Its development is favored by climate change. All types of oak and, in exceptional cases, other deciduous trees, for example hornbeam, beech, birch or robinia, are attacked by it. The pest occurs preferentially in light, warm forests with a high proportion of oaks and on the sunny southern edges of these forests. Individual trees in parks are also gladly accepted.

Federal states most affected by the oak processionary moth:

• Berlin
• Brandenburg
• Saxony-Anhalt
• Baden-Wuerttemberg
• North Rhine-Westphalia
• Bavaria

Recognize oak processionary moths

In order to recognize an infestation at an early stage, it is important to be able to reliably identify the butterfly. The larvae of the oak processionary moth are nocturnal. On their back there is a broad and dark back line with fields covered with velvety hair. From the third larval stage, long stinging hairs are formed. From the fifth larval stage onwards, the caterpillars create large webs of caterpillar silk, which serve as protection and nest for pupation. The behavior of the caterpillars gives it its name: The sociable animals often move one after the other as if in single file, as if they wanted to form a solemn procession.

The adult moths have a wingspan of about 3 to 3.6 centimeters and are hairy everywhere. However, your hair is not composed of stinging hair, so it is harmless. While the wings of the males show two clearly visible horizontal stripes, the stripes are less pronounced or nonexistent. The moths are also nocturnal, so they are relatively seldom encountered.

Harmful effects of the oak processionary moth

As a rule, an infestation with the oak processionary moth is very easy to cope with for a healthy tree. Even after they have been completely devastated, the affected oaks will sprout again well in the following year. However, repeated infestation over several years is problematic. Basically, the weakening can be caused by various abiotic (e.g. drought, heat, lack of water, frost) as well as biotic (oak powdery mildew, oak splendor beetle, Gypsy moth) factors lead to a relevant loss of vitality, so that in the forest, plant protection with food poisons must sometimes be carried out in order to prevent entire stocks from dying off to preserve. Especially in public green spaces, however, the spinner is primarily a threat to our health, because the stinging hairs can trigger strong reactions in the skin and the respiratory tract. You can read all about how to get one here Rash or other symptoms can avoid.

Development of the oak processionary moth

Following this paragraph you will find a table showing the development of the oak processionary moth. The female moths lay their eggs, about one millimeter in size, between the end of July and the beginning of September in the upper crown area of ​​oaks. A clutch can consist of 100 to 200 eggs and is arranged in the form of an elongated plate and carefully camouflaged. At the beginning of the vegetation period, the eggs hatch into the first larval stage, which is still yellowish-brown in color. This eats on the leaves of the oak and eats the entire leaf - only the central rib is spurned by the caterpillars. Depending on the weather, the first larvae of the third stage of development can be present from April. From this stage they have the typical stinging hairs, which are equipped with barbs and a nettle poison. Pupation takes place in June or July. After three to six weeks as a pupa, the adult butterfly hatches to produce the next generation.

Prevent oak processionary moths

A preventive plant protection treatment of oaks and other deciduous trees is judged by the Federal Environment Agency as not useful. In the case of particularly endangered trees, however, you should carry out repeated checks in order to be able to react in good time if an infestation occurs. Because chemical control measures, for example, can only be used in the first and second development stages. Such treatment is no longer possible by mid-May at the latest. In general, the promotion of natural opponents leads to a certain reduction in the severity of the infestation. An effective decimation of the warmth-loving oak processionary moth is only possible through longer periods of cold.

When is there a high risk of infestation for oak processionary moths?

• Oaks are in a monoculture or in an open landscape and with little undergrowth on other plants
• There was an infestation in previous years
• Nearby deciduous trees were infested in the previous year
• Mild winters and warm summers favor the development

Fight oak processionary moths

Fighting the oak processionary moth is difficult for various reasons. On the one hand, the butterfly prefers to attack trees that are already tall and these can hardly be treated with conventional spraying equipment. Second, getting close to a group of oak processionary moths is a very bad idea. Therefore never try to remove the animal yourself! If you are forced to stay near an infested tree, please note the following information.

Notes on staying near an infested tree:

• All skin areas must be protected as well as possible by clothing
• Do not touch the caterpillars and webs
• Wash clothes after contact at 60 ° C; Shower off your hair and body thoroughly

If there are problems in your private garden due to the presence of oak processionary moths, you really only have two left Possibilities: Either you avoid the infested area in order to avoid contact with the stinging hair - this is done by the Federal Environment Agency recommended. Or you can have the caterpillars controlled by a specialist company that specializes in pest control. The oak processionary moth can be fought very well with biological means - Bacillus thuringiensis – Preparations like ours Plantura borer-free XenTari^®are also used by specialist companies. For you as a private user, however, the product has not yet been approved for the oak processionary moth. Vacuuming and scraping are also common methods that are used. Burning or felling the infected plants harbors the risk of the stinging hairs spreading even further, whereby these methods are ruled out.

Does the oak processionary moth have to be registered?

At this point we would like to point out that there is no obligation to register for the oak processionary moth. However, you can and should voluntarily report an infestation in the private as well as public area to the responsible public order office or green space office. There you may receive further tips and, if necessary, remedial measures will be initiated.

More pointers on how to Avoid oak processionary moth rash can be found in our special article.