Illustration of a tiger mosquito.

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FotoshopTofs / Pixabay

  • The tiger mosquito appeared in the metropolis of Bordeaux in 2014, and in Bègles in 2015.

  • It is an exclusively urban species, which proliferates in the water points of our gardens.

  • This is why the city of Bègles is recruiting residents who will be trained to learn the gestures that save, and to disseminate them in their neighborhoods.

"In two months, everyone will talk about nothing more than that ..." warns Pierre Oualet, elected to the ecological transition in the city of Bègles.

“That” is the tiger mosquito, this famous tropical species that appeared in France in 2010 via the port of Marseille, and which landed in the metropolis of Bordeaux in 2014. In Bègles, it was identified for the first time in 2015, and since, it rots the lives of the inhabitants from the spring.

This year, the municipality of Béglaise wishes to take the lead.

These days, it is launching its first “Citizen Tiger Brigades”… The aim is to recruit volunteer residents who will be trained by the Bordeaux Métropole mosquito control center.

They will learn the life-saving gestures there, which they will share with their neighbors.

"These simple actions reduce by 80% the risk of the presence of mosquitoes nearby, and therefore of bites" assures the municipality.

"Talking between neighbors, to adopt a common attitude"

It is important to differentiate the traditional mosquito species from the tiger mosquito, because they have very different lifestyles and behaviors.

First of all, the tiger mosquito is an exclusively urban species.

"The tiger mosquito spawning grounds are in the city, not in natural contexts," insists Pierre Oualet.

This is why it is necessary to sensitize the inhabitants, who will be the best actors against the proliferation of the tiger mosquito, whose radius of action is a maximum of a hundred meters.

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These saving gestures are quite simple.

"It is a question of covering the collectors and the rainwater manholes, by making them completely hermetic, either with mosquito netting, or with silicone film which forms a film on the surface of the water, explains Christophe Courtin. , in charge of studies and coordination at the Bordeaux Métropole mosquito control center.

There are also biological anti-larval products.

And you must also monitor your mobile water receptacles in the gardens (furniture, wheelbarrows, watering cans, saucers of flower pots, etc.), which should be emptied regularly.

It is essential to walk around your garden once a month.

And we have to talk between neighbors, to adopt a common attitude.

"

The tiger mosquito usually occurs from May.

"After having spent the winter in the state of egg, it wakes up thanks to the warming of temperatures", specifies Christophe Courtin.

You can start inspecting your garden now, but it will be especially necessary to do it from April, and until the end of summer.

A first series of anti-larval treatment

At the same time, the fight against the traditional mosquito, which affects areas a little more remote from the metropolis, has started.

“What conditions the hatching of mosquitoes is water, which, in Bordeaux Métropole, comes 90% from precipitation,” recalls Christophe Courtin.

In 2020, we experienced two significant rainy episodes, the first in February-March with more than 100 mm in two weeks, resulting in a first wave of mosquitoes around March 20-25, then a second between April 20. and on May 10 with 150 mm of water, and a new phase of hatching behind.

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Is the heavy rains in December and January likely to in turn generate heavy mosquito outbreaks?

This is not the case for the moment, tells us the specialist.

First, because we are still in winter, and at this time of year the mosquito is generally still in the state of larvae.

Then, because the mosquito control center reacted immediately, already carrying out a series of anti-larval treatments, mainly on two species of mosquitoes.

"For the moment, we are not in the exacerbated conditions of last year", reassures Christophe Courtin.

But the areas to be inspected are so extensive, sometimes with inaccessible areas, and including private plots where Bordeaux Métropole cannot set foot except in special cases, “that we cannot however exclude the presence of mosquitoes from here. fifteen days.

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Avoid using treatments against adult mosquitoes

The mosquito control center can only intervene in the public domain of Bordeaux Métropole.

“Overall, the wetlands that we control are located on the Ambès peninsula, the municipalities of Parempuyre and Blanquefort, Le Taillan, Saint-Aubin, the forest areas of Mérignac and Pessac, then Bègles, Villenave-d'Ornon and Bouliac.

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These territories will continue to be inspected by the eleven members of the mosquito control center over the coming weeks, where they will only track larvae, knowing that they are also not authorized to use products against adult mosquitoes.

Only the ARS (Regional Health Agency) can trigger this type of operation, in the event of detection of a disease such as dengue, zika or chikungunya, spread by the tiger mosquito.

“On the other hand, individuals can use products against adult mosquitoes, observes Christophe Courtin, which we do not recommend, however, because these products are generally harmful and not very selective.

“Hence the interest in acting upstream.

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