Diamondback moths focus of Cornell study

The diamondback moth project at Cornell University isn’t a normal research project.

Cornell has created a detailed website for the project, the university has a media contact person specifically for the research and there is a Frequently Asked Questions link on the website.

Cornell entomologist Tony Shelton is testing a novel approach to control diamondback moths, a major pest of brassica crops including cabbage, broccoli and canola.

The caterpillars of diamondback moths feed on the leaves of brassica crops, stunting growth or killing plants.

Shelton and his team are working with a British company called Oxitec. Scientists at Oxitec discovered a method to alter the genetics of a male diamondback moth so that it passes on a “self-limiting gene” when it mates. Cornell is evaluating the effectiveness and safety of the technology.

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The self-limiting gene in the genetically modified moths produces a toxin in their female offspring. That kills the females before they reach adulthood and reduces the number of female moths that can reproduce.

The idea is to release genetically modified moths on cropland and with repeated releases, the population of diamondback moths in the area shrinks to nothing.

Diamondback moths are well suited for this approach because they breed rapidly and there is a short time between generations. As well, they are becoming resistant to a long list of insecticides.

“(It) is one of world’s most damaging insect pests,” Shelton said, noting that diamondback moths cause about $4.5 billion worth of damage to crops every year.

That may be true but research on moths normally doesn’t warrant a dedicated website or detailed videos explaining the science.

Cornell has gone the extra mile because changing the genetics of moths in the state of New York has generated a media frenzy in New York City.

The Atlantic magazine, Wired, Forbes, Bloomberg and the New York Times have all reported on the Cornell project.

Environmental groups and the public have raised alarms about the research. A comment on a United States government website, regulations.gov, summarizes their position:

“Future ramifications are unknown and could be dangerous to the entire world.”

Many have questioned the safety of releasing a genetically modified moth into the wild because it could pass the altered gene to other species.

Cornell, on its website for the project, said that scenario won’t happen.

“The released GE diamondback moths will only mate with their own species, producing offspring which carry the self-limiting gene.”

In 2015, Oxitec and Cornell tested the concept of GM moths in cages within a greenhouse. The tests showed that the Oxitec moths caused the diamondback moth population to crash.

In July of 2017, after more than a year of review, the U.S. Department of Agriculture granted Cornell permission to test the moths in a field setting.

Shelton and his team selected an eight-acre cabbage field near Geneva, New York.

“As of mid-October the field studies for the year have been completed,” the Cornell website stated. “We will analyze the data during the fall and winter and plan to submit a manuscript to a peer-reviewed journal soon after in 2018.”

Oxitec hopes the field study supports the technology because it may be safer than insecticides.

“The approach … is specific to the diamondback moth so does not affect beneficial insects,” the Oxitec website noted. “Additionally, the insects die out so the released insects and their genes do not persist in the environment.”

Diamondback moth larvae are a major pest for canola growers in Canada.

Most infestations occur when southerly winds carry the moths into the Prairies. The severity of the infestation depends on the population size in the spring and how early the moths arrive.

The Western Producer contacted Oxitec to see if the technology could be used on canola crops.

It didn’t respond by press time.

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