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
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
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
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.
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
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
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