Releasing sterilised males of an invasive fruit fly could make a big impact in curbing its population, which poses a severe threat to global fruit industries.
In the first trial of its kind, researchers released male spotted wing drosophila (Drosophila suzukii) sterilised with X-rays into tunnel-shaped greenhouses on three commercial strawberry fields in Kent, UK. On two of the sites, control greenhouses didn鈥檛 have the sterilised flies let into them. All three sites had seen similar levels of D. suzukii infestation in the three years prior.
At the start of the growing season in April, 9000 sterile flies were released per week in treated tunnels, rising to 60,000 in October as production of the flies increased. Numbers of wild females 鈥� a problem for growers because they lay eggs in ripening fruit resulting in larval damage to crops 鈥� were monitored using sticky traps, with counts taken throughout the season.
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Compared with the two control sites, populations of wild females were reduced by 71 per cent and 90 per cent in the field where researchers released the sterilised flies.
The sterile insect technique (SIT) works because sterilised males that compete to mate with wild females produce few or no offspring and so drive populations down. It has proved successful in controlling harmful insects such as the Mediterranean fruit fly and tsetse fly, and has long been considered a promising option for tackling D. suzukii, for which current control rests on the use of trapping and broad-spectrum pesticides.
鈥淪IT has a long track record of being able to outperform, and therefore substitute, chemical insecticides,鈥� says at BigSis, the UK company leading the work.
Sterile spotted wing drosophila are expected to be commercially available in 2023, and while tens of millions of insects would be required to service the UK鈥檚 fruit growers, BigSis can produce 5 million specimens a week, says Homem.
鈥淚t is excellent that scientists all over the world are looking into unique and innovative strategies to combat this troublesome invasive pest,鈥� says at Michigan State University.
鈥淭he results from these field trials look promising and are worth exploring in other systems. It surely is going to take a village to find long-term and sustainable solutions to [address these flies].鈥�
Insects
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