Genetically modified butterflies could herald a new era in crop protection

New study highlights successful test including field release of genetically modified butterflies. Scientists believe this success could pave the way for an effective and sustainable approach to pest control in crops.

The butterfly in question is the cruciferous moth ( Plutella xylostella ), or cabbage moth, a species of moth (butterfly) of the family Plutellidae. The agricultural industry has been trying for decades to find organic and environmentally friendly ways to fight the cruciferous moth, a species largely resistant to insecticides.

In order to counter this, a strain of these moths has been newly designed and field trials (in the United States), conducted by Cornell University, have been successfully conducted. These results are promising for future biotechnology crop protection applications and are also a potential solution for this global agricultural pest. In fact, this moth is very harmful to crops such as cabbage, broccoli, cauliflower and canola.

But now this new modified cruciferous moth strain, developed by Oxitec Ltd, has been specially designed to target and control these pests in agricultural crops. The new study showed that the modified strain had behaviors (towards cultures) similar to those of unmodified ringworms.

Scientists have genetically modified Plutella xylostella to develop a new sustainable strategy to protect agricultural crops from this otherwise harmful species. Credit: Shutterstock

In other words, the so - called Oxitec self-limiting butterfly is modified to control its harmful counterparts in the field.

How does it work?

After the release of males from this modified strain, the latter find and mate with unmodified and harmful females. Then, the self-limiting gene transmitted to the offspring prevents the female caterpillars from surviving. Scientists explain that with these prolonged releases, the pest population will be targetedly suppressed, in addition to being an environmentally sustainable solution. Indeed, after the cessation of discharges, the self-limiting insects decline and disappear from the environment in a few generations.

The field test is based on previously published work, which had been carried out in greenhouses, by Professor Shelton and his colleagues, who thus demonstrated that prolonged releases of the self-limiting strain effectively suppressed populations of pests and prevented resistance to an insecticide, a win-win situation for pest control. Note that this study was led by Professor Anthony Shelton, of the Entomology Department of AgriTech at Cornell University in New York. "Our research is based on the sterile insect management technique that was developed in the 1950s," reports Professor Shelton. "The use of genetic engineering is simply a more effective method to achieve the same goal,” he said.

Modified male butterflies as a crop protection solution

By observing the results in the field, in the laboratory, as well as by using mathematical modeling, the researchers gathered relevant information regarding the genetically modified cruciferous moth strain, whose unmodified wild counterparts cause considerable damage to around the world.

This study is the first in the world to release self-limiting agricultural insects in an open field. “To carry out the field study, we used the 'mark-release-recapture' method, which has been used for decades to study the movement of insects in the fields. Each strain was sprinkled with a fluorescent powder to label each group before release, then captured in pheromone traps and identified by the color of the powder and a molecular marker in the modified strain," explained Shelton.

Pest test results

"When released into a field, male self-limiting insects behave in the same way as their unmodified counterparts in terms of factors relevant to their future application in crop protection, such as survival and distance traveled Shelton reports."Our mathematical models indicate that the release of the self-limiting strain would control a pest population without the use of additional insecticides, as has been demonstrated in our greenhouse studies," he added.

According to Dr. Neil Morrison, chief agricultural officer of Oxitex and co-author of the study, the latter demonstrates the immense potential of this technology as an effective pest control tool, which could well help protect cultures from around the world in an environmentally sustainable way.


First Field Release of a Genetically Engineered, Self-Limiting Agricultural Pest Insect: Evaluating Its Potential for Future Crop Protection

Anthony M. Shelton, Stefan J. Long, Adam S. Walker, Michael Bolton, Hilda L. Collins, Loïc Revuelta, Lynn M. Johnson and Neil I. Morrison

Front. Bioeng. Biotechnol., 29 January 2020

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