Genetically modified moths could limit damage to crops

Genetically modifying diamondback moths to produce female offspring that don’t survive to reproduce could limit the amount of damage these pests do to cabbage, broccoli, and other types of crops, according to new research published in the journal BMC Biology.

A team of scientists from the US, UK, and China report that engineering the insects to ensure they have a “self-limiting gene” could be an effective way to suppress populations of their own species, ultimately causing the number of moths to decline dramatically.

According to BBC News, the genetically modified moths were developed by the Oxford-based company Oxitec, and they demonstrated that the technique proved to be effective in controlled conditions. USDA-approved field trials in which the GM moths will be studied under netting are scheduled to get underway later on this summer at New York’s Cornell University.

“We need this new technology to solve some old-world problems,” said co-author Tony Shelton, a professor at Cornell. Oxitec noted that the engineering method used in the GM moth is species-specific and that the self-limiting gene is non-toxic, meaning that the approach poses no threat to other insects or creatures that eat the moths.

Research promising as a non-toxic pest control method

In their BMC Biology paper, Shelton and his colleagues explained that they developed a male-selecting transgenes of the diamondback moth, Plutella xylostella, as a “direct, species-specific” method of pest management that allowed only male moths to survive until adulthood.

They reported that introducing these modified moths into wild-type populations led to a rapid decline in pest populations. In separate experiments involving broccoli plants, releasing a relatively low-level of modified males in combination with moths that were resistant to the bio-pesticide Bt (which is expressed in certain GM crops) suppressed population growth and delayed the spread of resistance to this pesticide.

The experiments, which were conducted in 2013, demonstrated that P. xylostella populations were brought under control within 10 weeks after the start of GM moth releases, and Oxtiec’s Dr. Neil Morrison told BBC News the results of the study would enable “pest control methods that are non-toxic and pesticide-free.”

“Within this model system we’ve been able to show that the Oxitec moths will delay the evolution of resistance to the Bt plants as well as lowering the pest population. So you have this double benefit,” Shelton added. “If you can combine the two technologies – Bt plants plus genetically engineered insects, you can have a more sustainable pest management system.”

(Image credit: International Institute of Tropical Agriculture)


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