Oak moth: This is why animals are so dangerous to humans

  • toLisa Klein


The areas are repeatedly cordoned off by the oak procession moth. But what is so dangerous about small animals?

Not only beetles, but also acorns are moving again. Time and time again, areas are cordoned off on a large scale. All because of the little caterpillars. But why actually? What dangers do oak procession moths pose to humans, animals and nature?

In Germany, all the federal states are now affected by the Oak Parade Mission, most notably Berlin, Brandenburg, Saxony-Anhalt, Baden-Württemberg, North Rhine-Westphalia and Bavaria. The oak procession moth prefers to live in dry and light places. Rich oak forests are especially settled, but are also found on individual trees, such as on roadsides and parks.

The oak parade moth is a moth, specifically a moth of the toothed moth family. The length of the butterfly itself reaches 25 to 36 mm, the females are slightly larger than the males. The animals are ash to grayish brown.

Oak moth: why are small animals dangerous?

What is dangerous in the oak parade butterfly is not the butterfly itself, but the caterpillar. Because the stinging hairs of the oak moth larva can lead to dermatitis in humans – a completely unpleasant allergic reaction to the skin.

The hair of the third larval stage, in which animals live in May-June, is especially dangerous for humans. Hair also sticks to clothes and shoes, and leads to toxic reactions when touched. Invisible stinging hairs easily penetrate the skin and mucous membranes and settle there using their hook.

The same goes for animals, by the way, dog owners in particular should make sure that their four-legged friends don’t enter enclosed areas either. Direct contact with the larva’s nose or tongue causes severe swelling in the head area and severe chemical burns to the dog’s tongue.

Oak moth procession: these reactions can occur by contact

Caterpillar dermatitis can lead to various reactions. Touching stinging hairs can cause the following symptoms:

  • severe itching
  • skin redness
  • pustules
  • pus blisters
  • Nodules resembling an insect bite reaction

If left untreated, skin reactions often last for one to two weeks. Usually all areas of the skin that are not covered are affected. Anti-inflammatory drugs are used as a treatment. It becomes more dangerous when the hair enters the mucous membranes. Irritation of the mucous membranes in the mouth and nose from inhaling hair can lead to bronchitis, painful cough and asthma.

If hairs are inhaled, inpatient treatment with cortisone or theophylline injections may be necessary. Associated general symptoms such as dizziness, fever, fatigue, and conjunctivitis may occur. In extremely rare cases, anaphylactic shock reactions are also possible.

Oak moth: a danger to humans, animals and nature

The oak moth is not only dangerous to humans and animals. The caterpillar is also considered a pest because it feeds on the leaves, causing defoliation or defoliation. In the event of a strong occurrence over several years, the tree can be damaged directly or through the consequences.

Beware of the oak moth parade! In Wertwiesen Heilbronn, affected trees were cordoned off over a large area in 2021.

© Melissa Sperber

As a rule, nothing is done to control the oak moth, except for forestry reasons. However, the oak moth has natural enemies such as bed bugs, parasitic wasps, caterpillar flies, cuckoos, oriole beetles and predatory beetles.

How can the dangers of the oak moth be avoided?

There are precautionary measures that are usually taken by the city or municipality. In order to avoid the infested areas, the surrounding areas were generously cordoned off with oak trees. There are also some other precautions that each of us can take:

  • Avoid endemic areas
  • Protect areas of the skin (such as the neck, décolletage, forearms and legs).
  • Do not touch the caterpillars and webs
  • Immediate change of clothing and showering with hair brushing after (possibly) contact with caterpillar hair
  • Refrain from logging or grooming measures as long as caterpillar nests are known

Oak moth procession: How long will areas remain off-limits?

Oak moth larvae are mainly found on oak trees. The egg clutches of 100 to 200 oak moths consist of white eggs about one millimeter in size. They are usually deposited on older oaks in the crown area on thinner branches and other areas of smooth bark in the form of an elongated plate.

Trees in Heilbronner Wertwiesen were infested with expedition oak in 2021.

© Melissa Sperber

The embryo develops into a fully formed small caterpillar in the fall, then spends the winter in the egg and hatches in early May. The larvae go through five to six stages of development until they hatch and are up to five centimeters long. They go in one coil in groups of 20-30 individuals in search of food, hence the name “parade moth”.

From the third stage, the larvae develop dangerous stinging hairs with spines, which contain nettle poison (thometopoin). Pupation of the acorn moth occurs at the end of June or the beginning of July, and even then the areas are likely to remain closed.

List of rules: © DPA Deutsche Presseagentur

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