New advances in nuclear techniques to eliminate insect plagues

The Sterile Insect Technique

Thanks to nuclear techniques, there are numerous methods to eliminate these plagues. The most widely applied technique, which has been in use for over sixty years, is the Sterile Insect Technique (SIT), which consists in a type of  insect "contraception": male insects are bred in large quantities; they are then sterilized with radiation and released so they can mate with females in the wild, and the lack of reproduction reduces the population. This technique is used to reduce agricultural plagues such as the Mediterranean Fly, the Tsetse Fly and cattle worms. More recently it is also being applied to Aedes aegypti and Aedes albopictus mosquitos, which cause plagues all over the world.

Spread of pests due to climate change

For some time now, climate change, transport between international markets, globalization and the resistance that some insects have developed to pesticides, make mosquito plagues spread out to new territories. At the beginning of 2000 there was a renewed interest in the application of the SIT technique to eliminate vectors of diseases such as dengue and malaria to areas where they did not previously exist. Later on, the Zika virus outbreaks in 2015 and 2016 evidenced the urgency of making advances in these alternative methods.

A publication by FAO/OIEA

The Food and Agriculture Organization (FAO) and the International Atomic Energy Agency (IAEA), both of which belong to the United nations, worked hard together to develop the set of SIT resources for mosquitos, and review them in a recently re-edited book with the latest advances:

Sterile Insect Technique - Principles and Practice in Area-Wide Integrated Pest Management

According to Rui Cardoso Pereira, head of the Insect Pest Control Section at the Joint FAO/IAEA Centre of Nuclear Techniques in Food and Agriculture, "countries are seeking alternative environment-friendly suppression methods, such as the SIT." "The book," continues Mr. Cardoso, "includes all aspects for its application - from preparatory feasibility studies to the implementation and monitoring of a SIT programme and latest research." This new edition also reviews strategic options for using the method—such as prevention, pest suppresssion or erradication—and discusses environmental considerations and socio-economic impact.

The book also includes the latest advances in the use of SIT extended to other harmful insects such as moths and beetles, and analyzes approaches to further improve this technique especially for mosquitos, by developing a genetic procedure that makes it possible to separate males from females for their release—an important aspect since the females bite and spread diseases.

Using Geographic Information Systems

Geographic Information Systems (GIS) technology is used to map out and study insect populations, so that the releases can be adjusted to the number of insects on site, which is more economic. "If you are releasing fruit flies over a 200 000 hectare citrus growing area, for example, the system will read the field data and release just enough sterile flies to compete with and suppress the wild fruit fly population," explained Mr. Cardoso.

Prevention of new plagues and future techniques

The book covers the use of SIT to tackle new invasive pests such as the spotted wing drosophila, a small fly that destroys soft fruits such as berries and cherries. Originally from Southeast Asia, the fly has become a growing problem in recent years in open fields and greenhouses across Europe and the Americas.

According to FAO and IAEA, there are plans to continue to improve mass insect breeding, procedures for genter separation and release systems as new sets of SIT-related resources for new species are developed.

Source: IAEA