Dominican Republic Uses Nuclear Technology to Win the War against Fruit Flies

Some could adapt more easily. Cory St Clair is a small producer in Cabeza de Toro. He had just planted chillies and red peppers when the ban was introduced, and he started looking for other markets. Now he sells mainly to Canada and Europe. “We were lucky,” he said. “But bigger exporters were not.”

Fear of the flies

While most of the flies were spotted in non-commercial almond trees along the coast, there was a fear that they might also invade commercial fruit and vegetable farms. Any appearance of the fly is seen as high risk and often causes countries free of the pest to restrict any imports of soft skin fruit and vegetables.

“We could have easily lost approximately US $220 million if the fly had reached the areas where the horticultural industry is concentrated,” said Minister of Agriculture Ángel Estévez, “which means losing around 30 600 jobs directly and indirectly. We are a small country, and the livelihoods of thousands of people working in the horticultural sector depend on exports.”

In 2014 and 2015, fruits and vegetables represented approximately 30% of food exports, earning the country around $610 million per year, according to the Central Bank of the Dominican Republic. The agriculture sector is also the third largest source of employment.

When the government detected the outbreak, it did not have the adequate institutional capacity to respond, Minister Estévez said. “For us, it became a trauma. I would go to sleep thinking of the fly, I would dream of the fly, and in the morning, I would wake up with the fly in my mind.”

Radiation to the rescue

When the Ministry of Agriculture asked for assistance in March 2015, the IAEA and the FAO helped the Ministry and its partners launch an integrated pest eradication campaign with the support of the Animal Plant Health Inspection Service of the USDA (USDA-APHIS), the Organismo Internacional Regional de Sanidad Agropecuaria (OIRSA) and the Inter-American Institute for Cooperation on Agriculture (IICA).

The authorities established an extensive network of traps along strategic spots to determine the spread of the pest, got rid of infested almonds, guavas and caya fruits, sprayed an insecticide mixed with a food attractant in hot spots, and imposed strict controls in the rest of the country, including at its ports and airports. But the key to contain the fly population was left for a nuclear-based birth control for insects called the sterile insect technique (SIT).

SIT involves mass-rearing male flies and sterilizing them with ionizing radiation. These sterile flies are then released from the ground and by air over pest-infested areas where they mate with wild populations, which subsequently do not produce offspring.

“It’s amazing to me,” said St Clair. “When I first heard about it, it sounded like science fiction.” Thanks to the intensive weekly release of millions of sterile Mediterranean fruit flies, which led to the control of the outbreak, the U.S. lifted its ban in 23 of the 30 affected provinces within 10 months.

SIT is among the most environmentally friendly control tactics available, and is usually applied as part of an integrated campaign to control insect populations. The IAEA and the FAO jointly support about 40 SIT field projects delivered through the IAEA technical cooperation programme in different parts of Africa, Asia, Europe and Latin America and the Caribbean.

Check this photo essay to learn more about SIT application in the Dominican Republic.

“We’re hitting the fly right where it hurts,” said Rafael Antonio Cedarro, a trap reviewer in La Romana, one of the areas still under surveillance. “In this area, we have 195 traps, and in the past three months we have trapped no wild fly.” These 195 are part of the 14 525 traps placed around the country to verify that the outbreak is under control.

“We’re impressed by the fast progress achieved in only a few months,” said Walther Enkerlin, an entomologist at the Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture. “Our job now is to provide advice on how to optimize processes further to achieve full eradication.”

Fly: 0, Caribbean: 1

The IAEA’s technical cooperation assistance, the coordinated emergency response and the Ministry’s containment of the outbreak have led to a number of knock-on benefits not only for the Dominican Republic, but for the entire region.

“The project has prevented the spread of the fly to other Caribbean and mainland countries, including Mexico and the US, avoiding large economic losses,” said Enkerlin.

The Ministry of Agriculture now has the necessary technical and human capacity to tackle this and other outbreaks and to share lessons learned and know-how, said Frank Lam, IICA representative in the Dominican Republic.

“It has been a costly experience that we want to share so that it doesn’t happen to other countries. We don’t want others to face this without being prepared,” Lam said.

Capacity building is another valuable spinoff from the IAEA project. More than 280 people are working under MOSCAMED-RD, the Ministry of Agriculture’s programme in charge of controlling and eradicating the outbreak. These have been trained in integrated fruit fly management, including SIT application.

“I have learned about a technology that I never in my life expected to learn,” said Ariel Brito Brito, one of the agronomical engineers working for MOSCAMED. “But I’m glad. It turned out to be excellent for my career and for my professional development.”

No future for pests

Analyses indicate that the Mediterranean fruit fly could have entered the country inside a tourist’s fruit bag in Punta Cana. Around five million tourists enter every year via the regional airport, accounting for more than 60% of the country’s annual entries. The majority of tourists come from Europe.

A phytosanitary barrier of 117 inspectors and X-ray machines now extends along the Dominican Republic’s maritime ports, airports and border points to ensure the fly doesn’t enter again. With very few exceptions, all fruits and vegetables arriving are confiscated and incinerated.

Minister Estévez is working together with his counterpart in Haiti to develop a strategy to protect the entire Hispaniola Island they share and avoid future infestation. “It’s not worth controlling the outbreak on one side of the island if it will appear on the other,” he said. “Insects have neither ID nor passport. But now we have the right capacity in place to face this invisible threat.”

This article was featured in the IAEA Bulletin, June 2017.