Breakthrough in GM insect technology for agricultural pest control

Oxitec scientists have for the first time been able to genetically modify the Diamondback moth, one of the world’s most damaging agricultural pests. This global pest, which attacks brassica crops such as cabbages and cauliflowers, is estimated to cost farmers $1Bn annually to control. Rising global food demand, environmental concerns and insecticide resistance are leading to pressure to find new ways to combat insects that reduce crop yield and quality.

Conventional pest control in agriculture rests heavily upon the use of chemical pesticides which are sprayed directly onto the food crop. Whilst effective against the target insect, insecticides can also have a harmful effect on non-target insects and environmental concerns have driven the search for less toxic and persistent chemicals. As chemicals have been withdrawn, the reliance on fewer products has exacerbated the problem of pesticide resistance in the target insect. Agricultural research has also led to the development of genetic modification techniques whereby the food crop is modified to express a protein to kill feeding insects. However, in both chemical control and GM crops, the control that targets the insect is applied on, or through, the food itself.

Oxitec, a UK company focussing on using GM insects for pest control, has pioneered a third way. Oxitec’s solution creates ‘sterile’ male insects that mate with wild females of the same species. The genetic modification prevents females in the next generation from surviving to adulthood, causing a decline in the target population.

In a study published by the journal ‘Insect Molecular Biology’ the Oxitec team details success inserting genes for inheritable fluorescent proteins in the Diamondback moth. This milestone, a world first, facilitates the development of the more advanced Oxitec modification that produces a ‘sterile’ strain of the species.

"GM technology in agriculture is normally associated with modification of the food crop and giving it a competitive advantage in terms of boosting its defence against insects” commented Dr Neil Morrison who leads the Diamondback moth project in Oxitec, “but at Oxitec we have taken an alternative approach; we harness genetics to provide the effect we want without making any permanent change to the species and without the gene persisting in the environment. So rather than use a recombinant DNA approach to give the crop a competitive advantage we give the insect itself a distinct disadvantage i.e. the inability to reproduce. Moreover, the modification is self-limiting as it relies on the concept of sterility, so is finite – it does not persist in the environment. This provides the potential for a safe and sustainable form of insect control.”

Dr Morrison added; “transforming the pest, as we are reporting here, is only the first phase. What will follow is a careful step-by-step process in development, evaluation and consultation. However brassicas are a hugely important food all over the world and the potential to provide a new safe and environmentally friendly form of insect control is very exciting.”