For the armed wing of the fight against the mosquito, the EID, it will be necessary to combine all the solutions tested to better coexist with the tiger mosquito, in particular, even if a pilot experiment – ​​an elaborate trap is very promising”. This is explained by Didier Moulis, the technical director of the Entente, which legally has only two products out of the ten existing before. Which could one day lead Diptera to enter into resistance…

There is the Camargue, the insect’s natural breeding ground, where no treatment is possible in this extraordinarily protected natural area. There is a coastline that is often over-urbanized, occupying former salt marshes and where the mosquito finds its ancestral habits, favored by the lack of authorized products to drive it away; there is global warming, more rainy episodes, and milder temperatures than before which awaken the ardor of the Diptera.

The tiger mosquito, accidentally imported from Asia, in a cargo of tires, says the urban legend colonizes more and more territories, invading the region for ten years Simard, head of the Vectopole of the IRD in Montpellier. A former student of Didier Fontenille (read elsewhere), adds: “Aedes albopictus is spreading more and more in Occitania.” Nothing will stop its expansion. The tiger is an invasive insect He’s the king of adaptation against which we are not quite defenseless.

Faced with a dramatic finding, including for tourism, Stéphan Rossignol, LR mayor of La Grande-Motte had alerted the public authorities and his fellow mayors on the coast, several of whom joined him in the face of this threat. In 2015, two years ago, he noted an “upsurge in mosquitoes now even at times when there were none before”. “It is difficult to assess exactly the extent of the nuisances, confides Didier Moulis, technical director of the EID, the Interdepartmental Mosquito Control Agreement. Sometimes 300 meters away, the situation is not the same”. But he swears the 2015 invasion “hasn’t happened again since. It had been favored by abundant rains in the spring followed by episodes of violent wind preventing the spraying planes from taking off and doing their job”. This is confirmed today by Stéphan Rossignol, adding: “We are on the edge every year…”

Worse, the arsenal of mosquito control is shrinking to a trickle, European standards oblige. This worries even the mosquito control specialists who have been questioning the Minister of Health for ages. The idea would be to launch studies to try to adapt products that already exist in agriculture. But these studies are prohibitively expensive… “ ANSES has launched experiments but all that is vegetating…”, grumbles Didier Moulis, technical director of the EID.

Two million euros in products and spreading

Technical manager at EID which spends more than €2 million each year on products and spreading (aircraft rental included), Didier Moulis reminds us that 80% to 90% of tigers take up residence with private individuals. “There is no miracle solution. You will have to combine several, such as self-dissemination.

Among the solutions, there is Reunion, a big program to sterilize males with gamma rays or X-rays. The eggs thus produced would not live. “That’s expensive. Too expensive. Mosquito factories must be built, not to mention the difficulty of explaining to the inhabitants that there will be, for a time, many more mosquitoes – and therefore tenfold nuisance – to perhaps have fewer in the end… “But this is an avenue that should not be neglected for the future, he says. We can perhaps have good results at the scale of a city.

As for the classic mosquitoes, Aedes detritus and Aedes which have never ceased to harass us, they risk putting our nerves on edge more and more precociously and for a long time. They love heat and humidity, which are likely to reign for the next few decades.

The track of CO2 traps, or carbon dioxide, which attracts the Diptera, is interesting. “Here too, we tested this solution, particularly on a campsite in Aude located right in the middle of a wetland, and also at La Grande-Motte and Le Grau du Roi. What we are sure of is that it will be at best an additional barrier; we are also testing degradable surface oils in the lab that can prevent mosquitoes from laying eggs and larvae from escaping.” In seven pilot municipalities of PO and Hérault, the EID is also conducting powerful field campaigns in all directions until the end of the year: traps therefore but also door-to-door public meetings, to convince the inhabitant to tackle this problem head-on There will be no miracle solution, warns Didier Moulis. You have to live with the “tiger”.

And maybe one day, man will put on his sorcerer’s apprentice clothes again, hoping that nature will forgive him. “There are beginning to be, not in France but in foreign labs, notably British, methods for transforming mosquitoes into living GMO organisms; we can now tinker with their DNA. We can insert a different gene there so that the mosquito defends itself against an infectious disease that it carries, such as dengue, and does not transmit it to humans. A healthy mosquito is already that. Unless, at the end of this necessarily risky manipulation, a monster comes out with an unknown evil gene. And even more indomitable…