Plans to release genetically engineered flies in Spain and Italy

Experiments may affect the production of olives

Thursday, 1 August 2013

The UK company Oxitec is planning to release genetically engineered olive flies into the environment in Spain (Catalonia) and Italy. The male insects are genetically manipulated in such a way that female descendants will die as larvae. The intention is to reduce the populations of olive flies. The larvae of these insects live inside the olives and can cause substantial economical damage. Oxitec plans to release an unspecified number of its genetically engineered male insects in Spain, near the town of Tarragona. The field trial will be netted to try to prevent the flies from escaping. Similar releases are planned in Italy. The experiments – as far as Testbiotech knows – have not yet been authorised by the national authorities, and it would be the first release of genetically engineered animals in the EU.

“Amongst other things, the trials imply risks for the olive farmers. If the genetically engineered flies escape, the harvest in the regions concerned would become nonmarketable. Genetically engineered larvae living inside the olives are not allowed for food consumption in the EU”, says Christoph Then for Testbiotech. “While the female descendants are supposed to die as larvae, the male individuals can survive for several months, mate and propagate further. If they escape, which according to the application of Oxitec, can not be excluded, they can move into the the environment and spread without control. Olive flies are able to fly over distances of several kilometers.”

Currently olive flies are controlled with insecticides, or by using biological means such as insect traps and also irradiated sterile insects. However, the genetically engineered insects, which also inherit the DNA for fluorescent proteins cannot be compared with the irradiated insects. The Oxitec insects are manipulated with synthetic DNA, which is a mix of maritime organisms, bacteria, viruses and other insects. It is not known how these insects will interact with changing environmental conditions, so far they have only been bred in the laboratory.

Christoph Then: “In 2012 Oxitec approached investors and commercial partners because of the releases now planned in southern Europe. The company also filed several patents on its insects. It is a matter of concern that these trials are driven by commercial interests rather than by finding a way to solve problems with olive flies. From the knowledge we have gained so far we recommend that these applications for environmental release are rejected.“


Dr. Christoph Then, Tel 015154638040,

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