To find where the colony lived, specialists captured insects and fitted them with mini radio transmitters. The nest was quickly located and destroyed.

KEYSTONE / AP / BOB EDME

A nest of Asian hornets has been spotted and destroyed in Geneva. The specialists used tiny radio transmitters attached directly to captured insects to locate the colony hidden in a lime tree. This large nest was neutralized Tuesday at nightfall in a residential area near the city center, according to the Department of Territory (DT). Firefighters from the Fire and Rescue Service, specially trained for this type of intervention, carried out the operation, which was a first in Switzerland, according to DT.

Since the first report of the presence of these hornets in July, a race against the clock has been undertaken to locate the point of origin of these invasive alien insects before the period of the fall swarms. Indeed, a hundred young queens could have left in order to create as many new colonies.

It was decided to use an innovative method, tested for the first time in France in 2018, to find the nest. Radio transmitters weighing less than 0.3 grams were attached to Asian hornets captured in the Eaux-Vives district. The nest, perched 22 meters high and largely hidden by the linden foliage, was thus able to be found.

Formidable predator

The colony was neutralized without incident. The destruction of this first colony testifies to the gradual establishment of the Asian hornet in the Geneva region. The authorities intend to slow down its progress given that this invasive insect is a formidable predator for honey bees already weakened by environmental damage.

The Asian hornet looks like a large wasp with a dark color. Its grayish, spherical nest can grow up to 80 cm in diameter. It is often hung from the top of a large tree.

Monitoring enabled

The Asian hornet has conquered Europe since its first arrival in southwestern France in 2004. Since then, it has been widely present in France. There have already been some sightings in Switzerland. The Geneva authorities had for their part activated a vigilance system for several years.

(ATS)