Defeating the Medfly

The Mediterranean fruit fly, or medfly, is one of the world's most destructive farm pests. It lays its eggs in fruit and vegetables, causing them to rot, larvae-infested on the ground. The medfly has menaced Latin America's fruit industry since its invasion early this century, depriving countries of food supplies and valuable export opportunities. The foremost victims have been small farmers, rural workers and the natural environment.

Medfly control and eradication became a priority issue in the 1990s for many governments in Latin America. Many have sought technical and financial support from the IAEA and UNDP, as well as from FAO and Interamerican Institute for Agricultural Co-operation (IICA).

Success in Chile

Agriculture is vital to Chile's US$ 44 billion economy. But by the 1980s, it was clear that the presence of medflies in Chile posed a major obstacle to developing the fruit and vegetable export industry. The Ministry of Agriculture launched a concerted extermination campaign using chemical and mechanical methods, i.e. pesticides and destruction of fruit, which required great sacrifice by the farmers. The medfly was confined to the Arica province in the northern tip of Chile by the end of 1980, but its presence there was enough to preclude the country's chances of winning significant export clients.

After several years of costly and unsuccessful control campaigns in the Arica province, the Government of Chile approached UNDP and IAEA for assistance in using the Sterile Insect Technique (SIT) to eradicate the medfly. The two agencies facilitated the launch of Chile's national SIT programme by bringing all concerned parties together in a series of meetings to discuss strategy.

The IAEA supported eradication efforts from 1987-1995 in a national programme initiated and funded in large part by Chile's fruit growers. Initially, sterile medflies were imported from Hawaii, Guatemala, and Mexico and released across Arica. Field results were so impressive that Chile decided to build its own plant. With contributions from an IAEA Technical Co-operation project, Chile built a factory for producing sterile medflies in the Arica near the border of Peru, which was inaugurated in August 1993. By December 1995, the medfly had been eradicated from Arica.

Chile's US $ 50 million battle against the medfly is rapidly paying dividends. Fresh fruit is Chile's third largest export product. Its agricultural exports were worth US $ 1 billion annually in 1996; with the medfly eradicated, annual exports are predicted to increase by US $ 500 million by the end of the decade. Chile now exports fruits and horticultural products to 50 countries throughout the world, and has recently entered lucrative markets in Asia. It is among the few countries allowed to export fruit to China and Japan.

Applying SIT to the Medfly

Medflies wreak havoc by injecting their eggs into maturing fruit and vegetables. One female medfly can produce up to 800 offspring per season. Rather than eliminating growing populations through massive pesticide doses, the SIT strategy is to release sterile medflies over large areas, preferably by air. The benefits of SIT can be summarized in terms of environment-friendliness, efficiency and effectiveness.

Environment: the disadvantages of insecticides are well known: residues in food, soil and water pollution and diminishing returns as pests develop resistance. By halting this vicious circle, SIT makes a genuine contribution to sustainable development.

Efficiency: pesticides can't reach every place flies hide; medflies can breed in back yards and even in urban areas where spraying is harmful. Moreover, pesticide campaigns depend on mass participation of farmers, which cannot always be ensured.

Effectiveness: the pesticide treadmill is costly and can amount to an expensive losing battle. SIT is the only pest control method able to achieve complete eradication. SIT is also effective because it is species-specific. Other biological control measures may have serious environmental consequences. For example, if the natural enemy of an insect pest is imported to an area, that parasite or predator might also consume or otherwise harm insects, plants or animals which are essential to ecosystem balance.

Extending SIT in South America

The success of SIT in Chile has spurred major new regional activities. A long-term plan has been formulated for medfly control in western and southern Latin America including Argentina, Bolivia, Columbia, Equador, Peru and Uruguay. It aims to secure medfly-free zones or suppression to the extent that exports are possible from major fruit-growing areas throughout the western half of the continent.

Chile is protected from a medfly re-invasion from the south and east by the Andes. But Chileans realize that the medfly could migrate anew from Peru. As part of its efforts to support Peru's development, UNDP and the IAEA helped establish a medfly rearing facility in La Molina near Lima in the 1980s. Though Peru had so far not been able to embark on a national eradication endeavor, the staff and facilities were crucial for the successful launch of a binational effort. In 1990, an agreement was reached between Chile and Peru for an eradication campaign administered by the IICA. The campaign is being carried out in two southern provinces with IAEA providing technical support and capacity- building, including training, for the entire country. Two irradiation plants are planned for the north and south, in addition to the updating of equipment in the La Molina plant.

In the south of Peru, eradication is foreseeable in the near future. In the tropical north however, the medfly shares its turf with the South American fruit fly. The IAEA is supporting Peru in its endeavors to adopt SIT for this variety. The project is still in the R&D stages, but small-scale rearing is already underway.

Argentina is widely known as a meat exporter, but in fact, exports as much fruit as meat. The Government sought assistance to protect its expanding fruit export industry against the medfly and trade restrictions which could ensue because of the pest. An IAEA Model Project targeting fruit fly eradication in the country's Southern Region began in 1994. Even by conservative estimates, Argentina expects to have fully recovered the costs of its medfly campaign by 1999. A 36% profit per annum is anticipated within twenty years of the project's launch.

SIT worldwide

The IAEA is assisting throughout the world in applying SIT to conquer pests that threaten food supplies and livelihoods. Methods have been developed to apply against a number of key pests, such as the screwworm, various caterpillars and a variety of fruit flies. UNDP and the IAEA have been involved in the joint Mexico-Guatemala cross border campaign to keep the medfly out of Mexico, where SIT has been applied since 1978.

Through IAEA-TC, Jamaica is battling the screwworm. UNDP facilitated the presentation of this new programme by including it in a recent donor meeting in Kingston. The US Government, through the Food for Peace programme, as well as the EU are likely sources of support to this new SIT campaign.

The eradication of the screwworm from North Africa in the early 1990s is considered one of the greatest pest control successes in UN history. Through a massive inter-agency effort, it was possible to eradicate the newly discovered pest using SIT and prevent enormous livestock losses. The Agency provided technical guidance through several projects.

Based on a recent study, direct and indirect losses due to the medfly within Israel, Jordan and the Terrorities under the Jurisdiction of the Palestinian Authority total US$ 192 million annually. Under the auspices of the IAEA, national projects were initiated aimed at area-wide control of the medfly using SIT. Eventually, this could lead to the complete eradication of the medfly from the entire region. Project activities started in the Lower Jordan Rift Valley in 1997. Some agricultural areas near the Israeli-Jordanian border had previously been declared Medfly free. Over the next few years, area-wide control of the medfly using SIT will allow the expansion of fruit free areas to include the entire Valley.

The EU is now providing funds for a fruit fly control programme in Madeira, Portugal, where the IAEA helped establish SIT capabilities. In addition, UNDP has requested the IAEA to participate in a fruit fly eradication project in Libya.

California is now using SIT very successfully to protect its US$ 18 billion fruit industry. The IAEA has provided important advice to this campaign through the Science Advisory Panel of the California Department of Food. And last but not least, SIT has also been successfully developed and applied by the IAEA to eradicate the tsetse fly from Zanzibar Island, Tanzania, proving its viability as a weapon against this insidious obstacle to agricultural development in Africa.

Contents
Foreword: Mohamed ElBaradei
Foreword: James G. Speth
Introduction: Building Development Partnerships
Better Feeding for Better Breeding
Ending Africa's Rinderpest Plague
Defeating the Medfly
More Rice from Less Land
Helping to Save the Black Sea