The Middle East’s Fruitful Valley - Bioflies

Published Date: 5 April 2007

© IAEA A bag of 7000 sterile Medflies, produced in the factory known commercially as Biofly. Set on a Kibbutz in Beit Shean, Israel, the factory is a mass breeding and rearing factory for the flies. From these Medfly pupae, adult flies will emerge. They will then be released in Jordan and Israel's shared Arava Valley. The Medflies are commercially bred for birth control; their mating yields no offspring. If left to multiply in the wild, Medflies wreak havoc on citrus and other fruit. The female attacks ripening fruits and vegetables by piercing the skin and laying its eggs inside. Fly eggs are "seeded" in trays filled with food for the larvae to feast on. This batch of eggs, sprayed onto white tissue paper, is wheeled to the larvae room for hatching. Millions of larvae squirm in feeding trays. The mesh netting encloses the maggots, as they jump and fall into trays where they are collected. The jumping maggots develop into pupae about the size of a grain of rice. It's a similar concept to a butterfly's cocoon -- safely inside the adult fly matures. Medflies are produced using a technology that enables the separation of the sexes, so that only male flies are produced. Here white female pupae and the brown males can be seen. Still in the pupae stage, the males are irradiated until sexually sterile. Thousands of live flies, sit in a rearing cage inside the factory. Inbar Shouster-Dagan holds a bag of the specially reared flies that are ready for release by hand on the ground. The sterile male flies are also released by air. Once the pupae in these bags become adult flies, they will be released in swarms by aeroplane to overrun the Arava Valley. Twice a week, Steve Carrigan becomes the friendly "fly bomber", releasing swarms of sterile male flies by air to overrun the Arava Valley. The sterile Medflies are transported to the aeroplane in a metal container. The specially converted plane is loaded with seven million flies. Once airbone, the flies are expelled in bursts and streams from a funnel leading to the outside world. Tomer Tene makes the two-hour flight from the Red Sea to the Dead Sea, to disperse the precious fly cargo in the Arava Valley. The plane dives low to release the sterile flies over villages, kibbutz and crops - all potential hot spots for Medfly infestation. It is the only aeroplane authorised to tick-tack between Israeli and Jordanian borders, in this Middle Eastern region where military "no fly zones" typically rule. The sterile Medflies are also released by hand, to reach areas beyond the plane's flight path. A prime focus today in Jordan is making sure that bustling cities like Aqaba in the south do not become potential "hot spots" for Medfly outbreaks that could place Valley harvests in the north at risk. This gardener explains that Jordanians like to grow fruit trees, like kumquat and lemon, in their backyards. Pest-control and monitoring programmes are strict in urban areas. The IAEA supported Jordan to implement the monitoring. Rashed Tayseer Al-Ashhab inspects backyards across Aqaba to check dozens of fly traps that hang in gardens across the city. It's a careful monitoring system designed to quickly alert authorities to any signs of Medfly. Mr. Tayseer Al-Ashhab collects flies for inspection at the lab. Flies are scrutinised under the microscope. They were collected from traps in Israeli orchards. This batch contains only the "friendly" sterilised Medflies, so there is no cause for concern. The sterilised flies are dyed as pupae to glow fluorescent orange under the microscope, to differentiate them from wild flies. "The good thing about trapping is that it lets us know the area. So we know when, and where, we need to release more sterile flies, if there is the slightest possibility of an outbreak," scientist Rachel Benamo explains. An outbreak would be a disaster for commercial orchards, so it's important to get it right.