Wild-type (brown) and two pupal colour mutations in the Mediterranean fruit fly, Ceratitis capitata. (Photo: G. Petrucci/IAEA)
For decades, most control efforts to manage insects that damage crops, affect livestock production or transmit diseases to people depended on insecticides. However, growing concerns about their risks to people, animals and the environment, as well as increasing insecticide resistance due to widespread use, mean new solutions for safe and effective pest control are urgently needed.
What is the Sterile Insect Technique?
The sterile insect technique (SIT) is a species-specific, environmentally friendly method for insect pest control. It has been used for more than six decades as part of area-wide integrated pest management programmes in countries and regions around the world.
SIT relies on releasing large numbers of sterile male insects into the environment. When these males mate with wild females, no offspring are produced, leading to a gradual decline in the pest population. The proven effectiveness of SIT across multiple target species has increased demand for SIT applications by member states of the IAEA and the Food and Agriculture Organization of the United Nations (FAO).
Why is Genetic Sexing Important for SIT?
Genetic sexing for SIT refers to methods of separating large numbers of insects by their sex. Ensuring that only sterile males are released is essential to the effectiveness and efficiency of SIT, so genetic sexing strains (GSS) play a crucial role. GSS enable mass-rearing facilities to easily separate males from females before release. This is especially important for insect disease vectors such as mosquitoes, because only females transmit pathogens.
Generic Strategies for Genetic Sexing for SIT
A generic approach for developing genetic sexing strains for SIT applications is a key outcome of a recent IAEA coordinated research project (CRP) conducted through the Joint FAO/IAEA Centre of Nuclear Techniques in Food and Agriculture .
Developing genetic sexing strains for insect species has traditionally required long, complex and species-specific research efforts. The new generic approach marks an important step forward in expanding sustainable pest control options worldwide across a wide range of insect species.
Over several years of collaboration, 24 scientists from 19 countries developed generic strategies that can be used to construct genetic sexing strains for a variety of insect pests and disease vectors. This enables future GSS development to be faster and less resource intensive. The team also examined how well these strategies perform across different types of insects. Understanding the range of species to which these methods are applicable helps determine how widely they can be adopted in future SIT programmes. In addition, several newly developed GSS were evaluated at small scale; early pilot evaluations are an essential step that must be taken before mass-rearing and operational testing can be conducted.
Participating researchers produced more than 140 peer-reviewed scientific publications and made numerous presentations at international and national scientific meetings, and in early 2026, the scientific journal Insect Science will publish a special edition featuring 18 articles highlighting the project results. This body of work will serve as a valuable resource for researchers and pest control programmes worldwide.
Any new genetic sexing strains developed using these new generic approaches must undergo further validation before they can be deployed in large SIT programmes. This includes testing under mass-rearing conditions and conducting small-scale pilot trials to confirm that the strains perform reliably.
