Oak and pine processionary caterpillars officially classified as harmful to human health

These particularly stinging insects that proliferate in pines and oaks are dangerous for people, but also for animals. A decree dated April 25 adds them to the list of species whose proliferation is harmful to human health.

You must have seen them: caterpillars which on or under the trees, move in single file…

With global warming, they have made the country their territory and with spring, the pine processionary caterpillars – Thaumetopoea pityocampa and oak -Thaumetopoea processionea were out again.

On the Mediterranean coast, they are now buried for a new cycle, chrysalises, then butterflies by July.

Since April 25, the caterpillars are (finally) considered as “harmful animals” to health. A decree has been published in the Official Journal, processionary caterpillars will therefore be included in the Public Health Code.

The caterpillar does not really impact the health of the plant, it weakens the tree but does not kill it. The problem is when the infestation rate is high in places that welcome the public, gardens, schools, hospitals…

Lucile Arnaud, pest monitoring coordinator garden and green spaces FREDON PACA

Another decree issued the same day designates the FREDON-FRANCE network of experts – which oversees the observatory of species at stake for human health – to coordinate measures for the prevention and control of these insects.

It is therefore this network of organizations with health services – there is one for each region – which will coordinate the actions according to the prefectural decrees taken locally.

Here is the butterfly – Thaumetopoea pityocampa whose eggs laid in August will give rise to the processionary caterpillar. There will be a total of 8 stages in this annual cycle.

And it is against this butterfly that part of the struggle takes place.

It’s per period. There are years when there are a lot of processionary caterpillars, others less. In PACA, the infestation rate is high, but less than in other regions, it is a fight on all fronts.

Some municipalities have opted for pheromone shots, during the period when the butterflies lay eggs.

In Saint-Laurent-du-Var or Hyères, for example, the chosen option consists of firing a mixture of sexual confusion pheromones, water and wax to prevent the reproduction of butterflies. Organic, nothing but organic, with the idea being to saturate the atmosphere around the trees.

Cagnes-sur-Mer has, for its part, decided to trap the caterpillars as they descend from the trees with bags, eco-traps which retain them.

Other municipalities or individuals have placed nesting boxes for tits, cuckoos or bats, these animals which devour without moderation these caterpillars, chrysalises or butterflies.

For Lucile Arnaud, eradicating processionary caterpillars is a combination of all these actions, which must be carried out at the right time of the year, and every year!

Caterpillar hairs are particularly stinging when touched. Allergy, skin rashes, conjunctivitis, respiratory disorders, the effects can be dangerous for health.

Some tips :

  • Avoid frequenting areas near infested pines, wear covering clothes if you go to these areas despite everything.
  • Avoid contact with caterpillars and nests.
  • No sweeping procession of caterpillars that would create a cloud of stinging hairs.
  • No laundry outside near the pines in high winds.

In the event of contact, the stinging hairs attaching themselves to the hair and clothing, it is recommended to:

  • A lukewarm shower with careful washing of the hair with shampoo.
  • Wash contaminated clothing above 60°C.

For animals, consult a veterinarian as soon as possible.

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