Development and Evaluation of Improved Strains of Insect Pests for Sterile Insect Technique (SIT) Applications

Objective:

  • To transfer existing technologies (genetic and/or molecular) for the construction of sexing strains in key insect pests
  • To develop and integrate molecular and genetic marker strains to monitor released insects in the field, to tag transgenes and to determine the mating status of females in the field
  • To establish targeted and stabilized transgenic strains to expand the safe and effective use of improved strains for SIT
  • To encourage and attract participants to the CRP in the field of Lepidoptera genetics.

Activities:

The sterile insect technique (SIT) is an increasingly important component of area-wide integrated pest management (AW-IPM) programmes for certain key insect pests. The use of this technology is meeting the needs of Member States as they deal with the impact of globalisation and climate change on the increasing problem of invasive pest species. The SIT has the ability to eradicate new outbreaks of pests so as to prevent their establishment. Among the major threats to agricultural production and trade are fruit flies and Lepidoptera pests and these are major targets for ongoing and future SIT programmes. Globalization and climate change are also leading to an increase in new outbreaks of mosquito borne diseases and major efforts are underway to develop new control techniques, including the SIT, for the mosquito species responsible for these outbreaks.

Operational use of the SIT continues to reveal areas where new technologies are needed to improve efficiency and thus lead to more cost effective programmes. There are many options for increasing the efficiency of the SIT, e.g. improved mass-rearing, release technology, quality control, etc, even when operational programmes are already underway. However, one critical area identified by programme managers where important advances can be made concerns the improvement of the strains themselves that are being reared and released. One example of how strain improvement can significantly enhance efficiency has been the use of genetic sexing strains (GSS) in SIT programmes for the Mediterranean fruit fly Ceratitis capitata. A technology developed through the Agency's CRP programme with support from the Entomology Unit of the FAO/IAEA Agriculture and Biotechnology Laboratory in Seibersdorf.

SIT programmes are currently being implemented for several very important fruit fly and Lepidoptera species where the development of improved strains would lead to major increases in efficiency of the SIT component. This new CRP focused on these species. For mosquitoes, where released sterile females would still act as disease vectors, strains such as that developed for the Mediterranean fruit fly which allow the release of only males are essential for the development for SIT.

Strain improvement can be achieved using different approaches, but all rely on some form of stable genetic change being introduced and maintained in the improved strain. Genetic change can be introduced either using classical genetics (as in the case of medfly GSS) or modern biotechnology, specifically genetic transformation. Both approaches have advantages and disadvantages relating to transferability of systems between species, stability in mass-rearing, regulatory approval etc.

Of significance to the use of genetic transformation, is the adoption of a standard (RSPM No. 27) produced by the North American Plant Protection Organisation (NAPPO) which provides guidelines for the confined release of transgenic insects. This confinement includes transgenic insects that have been sterilized by irradiation in SIT programmes.

The two most important areas which can be considered as targets for the development of improved strains for SIT field programmes are 1) strains that allow for the production of males only for sterilization and release (GSS) and 2) strains that incorporate a genetic marker to reliable and cheaply differentiate released insects from wild insects (marker strains). The major outcome of the use of these improved strains will be a more cost-effective and efficient implementation of SIT programmes for major insect pests of agriculture and human health.

Participants:

Thirteen participating countries: Australia, Argentina, China, Czech Republic, Germany, Guatemala, Greece, India, Italy, Mexico, Spain, Thailand, and USA.

Reports: