(AGENPARL) - Roma, 12 Gennaio 2026 - (AGENPARL) – Mon 12 January 2026 PressReleaseFinal3.jpg
INTERNATIONAL ATOMIC ENERGY AGENCY
12 January 2026
Preliminary Results Show Promise for Sterile Insect Technique Against Invasive Mosquito in Graz, Austria
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The Aedes albopictus (also called the Asian tiger mosquito) was first detected in Austria in 2012 and has since spread to all provinces of Austria. Graz experienced particularly high mosquito densities in the past years and in response to increasing nuisance reports, and rising arbovirus risk in Europe, the City of Graz requested the support of the IAEA, headquartered in Vienna, to initiate a Mark-Release-Recapture (MRR) study. 
The MRR study involves the release and recapture of a known number of marked – colour-dusted – male sterile mosquitoes in a defined area to investigate the local Ae. albopictus population and assess the feasibility and public acceptance of applying the SIT, a nuclear-based technology designed to manage insect pest populations.
Over a seven-week period in August and September, over 800,000 sterile male mosquitoes were released across a 15-hectare area of allotment gardens in the south of the city. Produced in the Insect Pest Control Laboratory of the Joint FAO/IAEA Centre of Nuclear Techniques in Food and Agriculture, the released male mosquitoes had been sterilized with radiation meaning that when they successfully mate with the wild females, no offspring is produced. 
Mosquito populations, including invasive species such as Aedes albopictus, are expanding rapidly across Europe and globally due to changing weather patterns, urbanization, and increased international trade. Warmer temperatures and altered precipitation levels create favourable breeding conditions, enabling species once confined to tropical regions to establish in temperate zones. This expansion poses growing public health challenges, as these mosquitoes are vectors for diseases such as chikungunya, dengue, and Zika virus. 
Analysis from recaptured mosquitoes within the MRR study – conducted jointly by the City of Graz and the IAEA – provides key scientific data on the size of the wild mosquito population, the distance sterile male mosquitoes can travel, their survival in natural conditions, and mating competitiveness in the field. 
“The preliminary results give us the basis to determine how best to apply the Sterile Insect Technique in Graz,” said Hanano Yamada, entomologist at the Joint FAO/IAEA Centre of Nuclear Techniques in Food and Agriculture. “The information is essential for determining the scale, frequency and geographic coverage of the future sterile mosquito numbers to be released as part of this pest control measure.”
Early results from the Graz study showed that the released sterile male mosquitoes were highly effective. About 70% sterility in the eggs was achieved, and the number of female mosquitoes caught in traps decreased over the study period compared to a nearby untreated area. This shows that sterile males can successfully compete with wild males and that their release can significantly reduce mosquito populations in high density urban environments.
The Graz study provides critical technical insights for planning future SIT trials under Austrian conditions, including sterile male dispersal, longevity, mating performance and overall operational feasibility. 
Based on the results, the City of Graz and the IAEA are preparing recommendations on next steps for the 2026 mosquito season.
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About the IAEA
The International Atomic Energy Agency (IAEA) serves as the world’s foremost intergovernmental forum for scientific and technical co-operation in the peaceful use of nuclear technology. Established as an autonomous organization under the United Nations (UN) in 1957, the IAEA carries out programmes to maximize the useful contribution of nuclear technology to society while verifying its peaceful use.
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