Here's a site you could check out http://france-nuisibles.fr is a paid for directory listing qualified pest controllers in France. There might be one close to you. Click in the pest (chenilles) then add your postcode where required.
I cannot vouch for them, but all will be qualified.
They are the vilest things ever! Have had a good response from our friendly farmer who feels it’s in his interests to get the big guns in & get the nests down, followed by the trees where they’re living. Good luck!!
Farmers etc [should] have Certiphyto which is the basic understanding and authority to use products on their land. The Certibiocides replaced DAPA, which I held for 5 years.
I can buy professional pest control insecticides and rodenticides etc in bulk and can use responsibly, ha ha....I can't sell direct to the public, so please don't ask!
I am also registered with SIMMBAD a gourvenment agency where I have to inform what quantities of products I use.
The SIMMBAD website is useful to the public for resourcing technical data (fiche de securité) such as antidotes, first aid etc.
Yes, just conifer trees from the genus Pinus, yew is Taxus I think but definitely not a pine. Nuts, box and so on are no problem. Only coniferous, not deciduous trees. Pinus syslvestris, Scots pine, is the number one culprit, Norway pine sometimes called red pine is a North American import that gets smothered by the buggers. Thank Napoleon for his inspiration to increase conifer cultivation for cheaper wood.
I'm rather alarmed by your assertion that 'just one can kill a cat'.....
Is it positive that just pine species are affected ? I have two enormous Yew trees, a couple of old walnuts and an apple tree.....various box hedges and boules....
Such useful information here - thank you! Can anyone tell me if we are doing the right thing to pour boiling water on the marching chenilles, then to burn them? We have 4 heavily infested trees and are trying to decide what to do long-term, but we’re hoping this will keep us safe until we can get an expert in to advise us.
We just had 3 large pine trees felled at a cost of 120€ for an hour's work: two men and a large tractor mounted cherry-picker. We don't have your caterpillar problem but I do sympathise as they are obviously a thorny pest. I expect that the lumberjack/bûcheron guys would want lots of loot to tackle trees infested with these beasties. I am told, however, that the insects need to come down to the ground to breed and that a special sticky band wrapped around near the base of the trees can catch them. Worth looking into. Perhaps some enterprising person will start a service spraying them with a purpose built drone.