Invasions of processionary caterpillars: “We are not fighting to reduce the species but to protect ourselves”
More and more precocious but still just as dangerous. While processionary caterpillars show up exceptionally early this season in the Paris region, Jérémy Thomas, professional based in Jouars-Pontchartrain (Yvelines) and manager of the company DGF 78, recalls the risks for our health and, above all, that of our animals. He has noticed an increase in his activity since 2020.
What impact have you seen on your business in recent years?
Jérémy THOMAS. For my part, I have recorded 20% new customers each year since 2021. For around 200 interventions per year, just for processionary caterpillars and only in Yvelines. We observe a multiplication in the number of cocoons on the trees. We try to make people understand thattreatment must be carried out even before the appearance of these cocoons on the oaks and Pines. A single cocoon contains a hundred caterpillars! Global warming accentuates the problem. Because there are two conditions for the processions. First of all, the caterpillar must be adult. Then, it is necessary that weather conditions are favorable, around 15°C. We’re not far from it at the moment.
How can we effectively combat the proliferation of these caterpillars?
The caterpillar is the harmful part, the butterfly the reproductive part. As professionals, we offer two treatments. The first is phytosanitary (BTK). It is applied at the end of summer, just after laying eggs in the trees. It is a mixture of bacteria and water, which destroys the digestive system of caterpillars. This reduces the number of caterpillars by 85%. We are not fighting to reduce the species, but to protect people and animals, because it is deadly for cats and dogs. The second treatment consists of placing a trap collar, a strapping around the trunk, around mid-November and until April, during processions.
VIDEO. “They can eat your dogs’ tongues!” »: the danger of processionary caterpillars
What precautions should you take if you discover them in your garden?
The best thing is to have a trap, and stay away if you find one… and be careful of the wind. These caterpillars are very stinging in the adult stage. So in procession, when they descend in single file from the trunk to bury themselves, they can reach the lawn and be in contact with children. In case of wind on a procession day, the hairs come off the caterpillars and can sting us. What can lead to complications, allergies… Animals can die if the respiratory and oral parts are affected. The tongue swells and edema can create choking. Animal owners are very aware of this.
