French city of Illkirch plans to test sterile insect technique to combat tiger mosquitoes

Thibaud Philipps, Mayor of Illkirch-Graffenstaden in France's Bas-Rhin department, hopes to pilot the Sterile Insect Technique (SIT/TIS) locally, sterilizing male tiger mosquitoes through radiation and releasing them regularly to curb population growth.

According to local authorities, tiger mosquitoes have been officially established in Illkirch-Graffenstaden since 2019. In recent years, the local tiger mosquito population has continued to increase, significantly impacting residents' daily lives. The municipal government has previously implemented multiple control measures, including launching the "Tiger Team" project in 2024 to educate the public on mosquito prevention and control methods, as well as providing subsidies of up to 50 euros per household for purchasing mosquito traps. To date, approximately 400 households have received relevant trapping equipment, but the tiger mosquito problem remains unresolved.

Against this backdrop, Philipps has submitted a proposal to the Prefect of Bas-Rhin, requesting permission to conduct a sterile insect technique trial within the municipality. The basic process of this technique involves rearing male mosquitoes in captivity, sterilizing them through radiation exposure to render them incapable of reproduction, and then releasing them into the environment. When sterilized males mate with females, the eggs laid by the females fail to hatch, gradually reducing the mosquito population.

Since 2025, similar trials have been conducted in several cities in southern France, including Montpellier, Brive-la-Gaillarde, and Toulouse. The private company responsible for these projects claims the system can reduce mosquito populations by 50%. However, results from these cities have not yet been published. Laetitia Delsemme, a mosquito control specialist, noted that this technique faces relatively high costs, as affected areas require weekly releases.

In a letter dated August 10, 2026, addressed to the Prefect, the Illkirch-Graffenstaden municipal government expressed its willingness to "provide services" and "mobilize the necessary financial resources" for the trial. Philipps stated that the municipal government hopes to collaborate with relevant national authorities and regional health agencies, and to evaluate the trial's outcomes.

The municipality may commission companies with experience in radiation-sterilized mosquito control to carry out the male mosquito sterilization work. According to available information, Aerial-CRT has 40 years of experience in radiation-sterilized mosquito control and has conducted research collaborations on applying this technique to other insect species. Delsemme noted that one of the current primary challenges is the limited supply of mosquito sources, requiring the construction of indoor rearing facilities for egg hatching and the separation of males from females.

Beyond improving residents' daily lives, controlling the tiger mosquito population is also linked to disease transmission prevention. In 2026, a case of dengue fever was reported in Illkirch-Graffenstaden, and a case of Zika virus infection was reported in the neighboring town of Eschau. Tiger mosquitoes are one of the key vectors for these diseases.