Paintball guns used in fight against processionary caterpillars in Brittany

A commune in Brittany is combating the proliferation of processionary caterpillars by using paintball guns to fire pheromone pellets into trees where the insects are nesting.

The technique disrupts the reproductive cycle of male moths, resulting in fewer caterpillars being born.

“As part of the fight against processionary caterpillars, the municipality has mobilised new resources. This biological control technique involves spraying pheromones onto nesting sites, which disrupt the moths' reproductive cycle,” the commune of Guidel in Morbihan said.

The method and the products used are harmless to both humans and wildlife, it added. 

The fired paintball pellets contain a mixture of water, beeswax and pheromones, allowing the pheromones to adhere to branches and disrupt mating.

The paintball guns allow technicians to reach the upper branches of pine trees, where the pellets burst and disperse their contents. 

The initiative includes the treatment of more than 130 pine trees with paintball guns, while around 40 pheromone traps are also being installed in oak trees to combat the oak processionary caterpillar.

The treatment remains effective for around four months, covering the moths' reproductive cycle. 

Since April 25, 2022, processionary caterpillars have been classified in France as a species harmful to human health. Covered in tiny toxic hairs, the insects can trigger severe reactions in both humans and animals. 

Their numbers are increasing this year, and anyone who spots them is encouraged to report sightings.

If pets or infants are exposed to processionary caterpillars, they should be taken to a medical professional immediately. Symptoms of exposure include severe itching and rashes, conjunctivitis, sneezing, sore throat, difficulty swallowing, breathing difficulties, excessive salivation, vomiting and abdominal pain.