Suppressing Moth Pests

The IS technique was first tested in the 1960s against codling moths which attack apples, but is now routinely applied to many other moth species of economic importance. With IS, specialized factories produce large numbers of the target moth pest, treat them with a specific “sub-sterilizing” dose of gamma or X ray radiation, and sequentially release them into the field.

Sub-sterilizing dose. As the term “inherited” sterility implies, the radiation dose is kept at a sub-sterilizing level to ensure that the treated insects released in the field remain viable for mating. However, the dose of radiation they receive ensures that they will produce fewer offspring in the first generation, most of whom will be males and completely sterile. As a result, continuous release of substerile moths will result in a gradual reduction in the natural moth pest population.

Area-wide IPM approach. IS plays a major role in controlling moth pests that attack commercial commodities and ornamental plants. However, because of the migratory nature of moths, IS cannot be applied on an orchardby- orchard or field-by-field basis. Success depends on its being applied as part of an area-wide integrated pest management approach using a suppression or eradication strategy against an entire pest population in a delimited area. The validity of this approach to suppressing or eradicating moth pests has been demonstrated in Canada, Mexico, New Zealand, South Africa and the United States and is under development in other countries.

The use of ionizing radiation to irradiate large numbers of insects is the key to IS. There is no acceptable alternative that could replace radiation-induced sterility in this process. As every single moth must be treated with a sub-sterilizing dose before release, irradiation remains a central and indispensable part of the total process.

When compared with conventional pest control, the advantages of the IS application are numerous. Unlike insecticides which affect human health and biodiversity, the IS application is:

• inherently safe and responds to increasing demands to protect the environment and human health, Suppressing moth pests Inherited sterility technique insures male moths are born sterile
• species specific, with no detrimental effect on beneficial non-target organisms, and
• uniquely effective in eradicating outbreaks of invasive pest species.

IS has been applied successfully against a range of devastating moth pests of economic, environmental and quarantine importance such as the pink bollworm, codling moth, false codling moth, cactus moth and the Australian painted apple moth.

Control of most moth pests has been hampered by their increased resistance to most of the commonly used broad-spectrum insecticides. Hence, there is considerable potential for expanding IS applications to other moth pests, such as the date moth, European corn borer, Asian corn borer, Asian rice stem borer, cabbage webworm, Oriental fruit moth, sugarcane borer, corn earworm, diamond back moth and European grape vine moth.

The use of IS is mostly driven by governments in active partnerships with the private sector and other national and international organizations that share a common vision. Aligning well organized fruit and vegetable producers with government initiatives is key to achieving success.

Through Coordinated Research Projects, the Joint FAO/ IAEA Division provides assistance to Member States in the development and implementation of area-wide integrated pest management projects that include IS components. In addition to the applied research and technology transfer, it provides capacity building, policy advice, and information management. It also promotes the development and application of phytosanitary standards, which facilitate international trade of fresh fruit and vegetables. Member States benefit from the technical support of the Joint FAO/IAEA Division’s Insect Pest Control Laboratory (IPCL) which conducts applied research in areas ranging from mass rearing and sterilization of insects to insect behaviour and genetics. It also maintains a reference centre for insect strains and mutants, and transfers technology by providing technical support and training, hosting consultants and visiting scientists for varying periods of time. To a lesser degree, it supplies basic materials and equipment, and training in the use of the equipment.