The warm spell in May prompted an increase in sightings of chenilles processionnaires (processionary caterpillars) in almost all areas of France. One ‘exceptional outbreak’ in particular, in Yvelines, near Paris, prompted the préfecture to close sections in the north and west of the popular forêt de Rambouillet to the public for more than two weeks. To the delight of joggers, hikers, and families, the forest trails are due to reopen on Saturday, June 13th – but officials have urged anyone visiting the forest to remain
cautious: “Vigilance is still essential, as processionary caterpillars and their stinging hairs are still present,” the préfecture said in a statement announcing the forest’s reopening. It recommends wearing protective clothing, avoiding contact with caterpillars, their nests, or trees on which their nests can be seen, and keeping children and pets under close supervision. It also advised visitors to wash their hands upon returning home. So why such a fuss about these catterpillars? Processionary caterpillars are a poisonous species of caterpillar that can be found in
oak or pine trees. Pine processionary caterpillars are orange-brown in colour, while oak processionary caterpillars are silvery-grey. Groups can often be seen ‘processing’ along trees and the ground in single file, hence their name. Their tiny and detachable hollow hairs can irritate skin and cause allergic reactions, including eye inflammation and breathing problems, particularly among children and anyone with allergies. In more severe cases, the sting can lead to a sudden drop in blood pressure, faintness or loss of consciousness. The hairs – they’re detachable,
remember – can be shed whenever the caterpillar feels threatened, and can be easily carried by the wind. Dogs are especially vulnerable, as even brief contact with a processionary caterpillar’s hairs can trigger serious reactions. Authorities advise people follow the following precautions if they come across the caterpillars, or are in areas where they are known to proliferate: Do not approach or touch the caterpillars or their nests: this applies especially to children; Keep away from trees containing their nests; Wear long clothing when walking
in the forest or near infested trees; Avoid rubbing your eyes during or after a walk; Wash fruit and vegetables from your garden thoroughly if there is any infestation nearby; Avoid drying laundry next to infested trees; If you suspect you have been exposed to the caterpillars, take a shower and change your clothes; In the event of any signs of a life-threatening emergency, such as respiratory distress), dial 15 or 112, or go to your nearest hospital emergency department; If any poisoning symptoms occur,
seek advice from a doctor or call a poison control centre; If you come into contact with a caterpillar, take photos of it for easier identification; If an animal shows symptoms such as excessive drooling, swelling, and/or trouble breathing, consult a vet. Unlike human cases, animals are more usually stung in the mouth. This is due to the way in which they are exposed: dogs licking or eating caterpillars, horses and ruminants ingesting contaminated plants. A major complication is tongue necrosis of varying degrees, which
can be prevented or limited by very prompt medical treatment. Lesions of the legs and digestive system may also occur. Preventive control of pine processionary caterpillars involves diversifying the species of trees. This approach is based on planting non-host plants that are not a food source for the caterpillars. Nests can also be destroyed, but only by dedicated professionals with specialist equipment – and only if a few readily accessible trees are affected. Trap collars can be placed around the trunks of pine trees before
winter, when the caterpillars descend from the pines to bury themselves in the ground.
forêt de Rambouillet, Yvelines, préfecture, chenilles processionnaires, processionary caterpillars, vigilance, stinging hairs, pine processionary caterpillar, oak processionary caterpillar, dogs, children, June 13