Whether we like them or not, genetically modified plants are being grown here in Australia and are a part of our food chain. But the latest announcement by the Western Australian government tells us that genetic modification in agriculture is moving beyond grains and cotton and into a new area.
The Western Australia Department of Agriculture and Food (DAFWA) yesterday announced they will conduct an indoor assessment of a fruit fly that has been genetically modified to contain a ‘self-limiting’ gene. This will prevent the female offspring from reaching adulthood so they cannot ‘sting’ fruit crops or reproduce. This goal is to shrink the pest population in the release area.
The Mediterranean fruit fly, or Med Fly as it is known, is a serious horticultural pest in Western Australia. It attacks a range of cultivated fruits and some fruiting vegetables, and costs the WA horticulture industry millions of dollars annually in lost production and control costs.
Growers use a range of methods to combat fruit fly, including pesticides, baiting and orchard hygiene, but the withdrawal of organophosphates from use in commercial orchards has led to renewed interest in innovative solutions against fruit fly.
The modified flies, called Oxitec Med-flies, have a fluorescent marker (DsRed2) to distinguish them from the pests so they can be monitored.
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The WA trials will occur within glasshouses, but in Brazil the GM fruit fly has already been approved for outdoor trials.
Professor Tony Clarke, Professor and Chair of Fruit Fly Biology and Management at QUT says, “The Oxitec Med-flies offer a new form of pest control, very closely related to the well-established Sterile Insect Technique (SIT). In the SIT, flies are mass-reared in factories, sterilised by irradiation, and then released into the environment where they mate with wild females. This causes the wild female flies to lay infertile eggs, and eventually the repeated release of sterile male flies can drive the field population to extinction.
“With the Oxitec flies, the general approach is similar, but in this case the mass-released male flies carry a genetic modification which means that all their offspring die. The released flies are environmentally safe and there is no known risk of genetic contamination from the released flies.”
“The Oxitec approach is not, however, without issues. The flies are genetically modified, and this greatly limits their use under current legislation. Importantly, the lethal gene must be ‘switched off’ in the factory, otherwise the flies could not be reared. This requires the addition of tetracycline hydrochloride to the fly diet. Tetracycline is an antibiotic and how the spent, tetracycline-dosed larval diet from a fruit fly factory (which may run to several tonnes per week) will be properly disposed of will need to be addressed.”
A 2012 poll found that up to 66 per cent of Australians preferred to avoid GM foods as they had some concerns about their safety. But how do we feel about genetically modified insects? And if fruit flies can be modified successfully what will be next?
How do you feel about genetically modified insects here in Australia? Do you think he public should be consulted before this work moves ahead?