In the two municipalities of Locarnese, two residential and tourist areas of approximately 12 hectares each have been identified, where the sterile male technique will be tested. Within these areas, 18 release points will be set up, distributed evenly every 50-100 meters. From June to September 2025, approximately 72,000 sterile males will be released each week. To assess the effectiveness of the method, data on the tiger mosquito population has been collected and analyzed since May, both within the release areas and in the surrounding areas. Monitoring is based on the collection of eggs and adults using specially positioned traps.
The experiment conducted in Morcote in 2023 and 2024 has already confirmed the effectiveness of the technique in the Ticino region and has made it possible to refine the operating procedures. The new phase of experimentation will make it possible to evaluate its applicability on a smaller scale, i.e., on specific portions of municipal territory, in urban contexts with different characteristics and population densities.
A larger-scale trial was planned initially, but a lack of funding forced the project to be scaled back. To ensure the continuity of the research, the municipalities of
Ascona and Losone were selected on the basis of scientific and operational criteria. In Losone, an area was chosen that includes a hotel zone and a special protection zone, such as the school district, with a low initial mosquito density, an ideal condition for assessing whether the technique can eliminate the population.
In Ascona, the area identified is located in a tourist context with a presence of second homes, ideal for testing the effectiveness of the technique in environments characterized by a fluctuating population, such as that of seasonal visitors.
The results obtained will be of both regional and national significance and will be fundamental in helping to lay the operational foundations for the creation of biofactories capable of supplying sterile males to municipalities or private actors, with the ultimate aim of containing the tiger mosquito both for its nuisance and for the health risk associated with its presence.
A strategic collaboration for the future of biological control
The project is the result of a collaboration between the Institute of Microbiology at SUPSI (Department of Environment, Construction and Design) and the Giorgio Nicoli Centre for Agriculture and Environment in Bologna, an international reference point in the production of sterile males. It also enjoys the scientific support of the World Health Organization.
The ongoing trial has been made possible thanks to the support of the municipalities of Ascona and Losone and private partners such as the Albergo Losone, which have contributed to the financing of the purchase of sterile males. In light of growing interest from other municipalities in Ticino, SUPSI is committed to accelerating the trial phases and gradually expanding the areas involved. The goal is to make the sterile male technique available on a regional scale by 2026-2027 as an effective, sustainable tool that complements current control measures.
The sterile male technique
If confirmed to be effective, the sterile male technique will complement current public and private interventions to contain the insect and reduce the risk of transmission of viruses such as dengue and chikungunya. The methodology is safe, environmentally friendly, and non-invasive. It involves the regular release of sterilized males during the summer months. Unlike females, males do not bite and therefore do not transmit viruses. On the contrary, they play an active role as they seek out females in the area to mate with. Once mated with a sterile male, the female will not be able to produce offspring. Regular releases lead to a progressive reduction in the population, as demonstrated in the municipality of Morcote, where between 2023 and 2024 there was a decrease in females of up to 63%.