Graz, Austria: A Potential Success Story for Sterile Insect Technique Against Invasive Mosquitoes
The International Atomic Energy Agency (IAEA) and the City of Graz have announced preliminary results from a groundbreaking study using sterile male Aedes albopictus mosquitoes. This study, conducted as part of an assessment for the potential future use of the Sterile Insect Technique (SIT), an environment-friendly pest control method, has shown promising outcomes in curbing the rising populations of the invasive mosquito in Graz.
The Aedes albopictus, also known as the Asian tiger mosquito, was first detected in Austria in 2012 and has since spread to all provinces. Graz, in particular, has experienced high mosquito densities, leading to increasing nuisance reports and a rising arbovirus risk in Europe. The City of Graz, in response, requested the support of the IAEA to initiate a Mark-Release-Recapture (MRR) study.
The MRR study, involving the release and recapture of marked male sterile mosquitoes, provided valuable insights into the local Ae. albopictus population and the feasibility of applying the SIT. Over 800,000 sterile male mosquitoes were released across a 15-hectare area in allotment gardens, south of the city. These mosquitoes, produced in the Insect Pest Control Laboratory of the Joint FAO/IAEA Centre of Nuclear Techniques in Food and Agriculture, were sterilized with radiation, ensuring no offspring are produced when they mate with wild females.
The analysis of recaptured mosquitoes within the MRR study revealed crucial scientific data. It determined the size of the wild mosquito population, the distance sterile male mosquitoes can travel, their survival in natural conditions, and their mating competitiveness in the field. Hanano Yamada, an entomologist at the Joint FAO/IAEA Centre, emphasized the significance of these results, stating that they provide a basis for determining the best application of the SIT in Graz.
The early results are highly encouraging. Approximately 70% sterility in the eggs was achieved, and the number of female mosquitoes caught in traps decreased over the study period compared to an untreated area. This demonstrates the successful competition of sterile males with wild males and their potential to significantly reduce mosquito populations in urban environments.
The Graz study offers critical technical insights for planning future SIT trials under Austrian conditions, including sterile male dispersal, longevity, mating performance, and operational feasibility. Based on these findings, the City of Graz and the IAEA are preparing recommendations for the 2026 mosquito season, aiming to further develop this innovative pest control method.
This study highlights the potential of the Sterile Insect Technique as an effective and environmentally friendly approach to managing invasive mosquito populations, particularly in urban areas. As the world grapples with the challenges of rapidly expanding mosquito populations and the associated health risks, such innovative solutions become increasingly vital.
