Processionary caterpillars: what are they?
Pine processionary caterpillars and oak processionary caterpillars are insects that live in colonies on pines or oaks. They are so nicknamed because they move in single file. Their proliferation can cause a weakening of the trees.
Their hairs are particularly stinging. They can cause inflammatory reactions, especially on the skin (redness, itching, skin pain, localized edema, hives and sometimes small blisters), the eyes (conjunctivitis, tearing, eye pain) or the respiratory tracts (cough, difficulty breathing), sometimes serious in people or animals exposed to it. No need to come into contact with the caterpillar to show symptoms: its stinging hairs come off and are carried very easily by the wind.
The pine processionary caterpillar is present over a very large part of the territory, mainly in the south, center and west of France. It is mostly seen between January and May.
The oak processionary caterpillar is mainly present in the north-east, the Paris region and the north-west of France, and can be present in southern regions. It is mostly seen between April and July.
ANSES, together with the poison control centres, analyzed the various cases of adverse effects linked to the stinging hairs of processionary caterpillars recorded between January 2012 and July 2019. The results are available in Vigil’Anses of November 2019 (PDF).
How to protect yourself from processionary caterpillars?
In order to limit the risks of poisoning linked to processionary caterpillars, here are some tips:
- do not approach or touch the caterpillars or their nest, especially for children;
- stay away from trees with nests;
- wear long clothes when walking in the forest or near infested trees;
- avoid rubbing your eyes during or following a walk;
- thoroughly wash the fruits and vegetables in your garden in the event of an infestation nearby;
- avoid drying clothes next to infested trees;
- if caterpillar exposure is suspected, shower and change clothes;
- in the event of life-threatening signs (respiratory distress, etc.), call 15 or consult the emergency room;
- in case of signs of poisoning, consult a doctor or call the poison control centre;
- if contact with the caterpillar, photograph the caterpillar to facilitate its identification;
- if pets are affected, consult a veterinarian or call a veterinary poison control center (Western Animal and Environmental Poison Center et National Center for Veterinary Toxicological Information).
> Consult our brochure on processionary caterpillars (PDF).
