For several years in Savoie, rising temperatures have come with bad news striped in black and white: the tiger mosquito. This invasive species is closely monitored because it can transmit diseases such as dengue fever, chikungunya and Zika.
The end of May is a key time to stem the momentum, as now is when the first tiger mosquitoes will hatch. “The form of resistance in mosquitoes is the eggs, it is with them that they spend the winter” explains Rémi Foussadier, director of the EID, Interdepartmental Mosquito Control Agreement, based in Chindrieux. “The females lay eggs in the fall. These wait for the summer season and if they are in water, they will give larvae”.
Now is the perfect time “to clean the house” explains Rémi Foussadier. Three words: empty cover, put away. In fact, it is a question of regularly emptying all the stagnant water in your garden, such as the cups of flower pots, and covering your water collectors with a mosquito net, for example. “Everything that is done now is a win for the rest of the season, because the populations of tiger mosquitoes have an exponential development speed and it is much easier to break the dynamic at the start of the season than in the middle” .
Installed in France since 2004, this mosquito is now proliferating throughout France. The Ministry of Health now lists 67 colonized departments and the two Savoies are not spared. According to the public authorities, more than 40% of the Savoyard population is affected.
The tiger mosquito first arrived in Aix Les Bains in 2014 before reaching Haute-Savoie in 2019. You should know that it does not fly further than 150 meters. Therefore, if it bites you at home, it means that the source of the eggs is in your garden or that of the neighbour. Moreover, it has proliferated in France by moving around in cars. In 2014, he even landed in Aix-les-Bains by setting up “proximity with an air of motorhome” relates Guillaume Rey, technician on environmental risks in Aix-les-Bains, in charge in particular of the management of tiger mosquitoes. “This suggests that he arrived by a motorhome”.
A characteristic that implies that the fight against the tiger mosquito must be local and global: each inhabitant has a responsibility. Some communities are also getting their hands dirty, such as the town of Aix-les-Bains, which has been experimenting with traps since last year. “These devices reproduce the spawning grounds to attract the female” expose Guillaume Rey. “These are complements to preventive actions.
It is necessary that this kind of gestures multiply, because the tiger mosquito is already well established in Aix-les-Bains, Annecy or even in the Chambéry basin. Above all, it continues to gain ground in the Combe de Savoie, and even in the valleys hitherto spared. The altitude does not scare him, because “the eggs can overwinter up to 800 meters” according to Rémi Foussadier. “If nothing is done, it will therefore continue to spread in the valleys” he warns.