U.S. Crop Tech Corner

Let's Hear It for the Maize: Studies Show Benefits of GM Corn

Emily Unglesbee
By  Emily Unglesbee , DTN Staff Reporter
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Two long-term studies reveal some unintended benefits of GM corn hybrids, including regional pest suppression and lower toxin levels. (DTN photo by Nick Scalise)

ROCKVILLE, Md. (DTN) -- This bi-monthly column condenses the latest news in the field of crop technology, research and products.

UNINTENDED BENEFITS OF BT

Farmers of genetically modified (GM) corn have long known the benefits of Bt traits. By controlling target insects with minimal or no chemical insecticide use, they save growers time and money. Now a University of Maryland study is asserting that non-GM vegetable farmers should be equally grateful for the technology. The widespread adoption of Bt corn is strongly correlated with large drops in insecticide use and insect damage in vegetable crops in the U.S., according to the Maryland scientists.

The study encompassed data from 1976 to 2016. The researchers scrutinized insect management and insecticide use in the 20 years before Bt crops were adopted and the 20 years after. They focused on the corn borer, which was targeted by the very first Bt corn hybrids to hit the market in the late 1990s. "This is the first paper published in North America showing offsite benefits to other host plants for a pest like the corn borer, which is a significant pest for many other crops like green beans and peppers," said UMD entomologist Galen Dively in a university press release. "We are seeing really more than 90% suppression of the corn borer population in our area for any crop, which is incredible."

Dively and his colleagues aren't done with the topic. "The next steps would to be quantify the millions and millions of dollars in economic benefits we see here in a very concrete way to show money and time saved on spraying and pest management, crop damage reduction, as well as consideration of the environmental benefits," he said.

See the study here: http://bit.ly/… and the UMD press release here: http://bit.ly/….

STUDY FINDS GM CORN LOW IN TOXINS

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After combing through 20 years of data on GM corn, Italian scientists found some surprising benefits. Not only did these corn hybrids tend to yield higher than their non-GM counterparts, but they also had significantly lower levels of mycotoxins and no negative effects on agronomic traits.

The researchers examined peer-reviewed literature from 1996 to 2016 on GM corn (herbicide-tolerant and Bt), focused on yield, grain quality, non-target and target organisms and soil biomass decomposition. They found that GM corn yielded 6% to 25% higher and had mycotoxin levels nearly 30% lower than non-GM corn, specifically 30% lower levels of fumonisin and 37% lower levels of thricotecens.

They also concluded that GM corn had no effect on non-target organisms with the single exception of a parasitoid that preyed on the European corn borer. Since Bt control of this pest has resulted in corn borer populations plummeting, the parasitoid has found itself without many hosts. Finally, they found that most agronomic traits were unaltered in GM corn, although biomass decomposition was higher in GM corn hybrids.

See the full study here: http://go.nature.com/….

WHITE MOLD NOT SO COLD

White mold is a serious disease for the soybean industry, but it has been mostly limited to the upper Midwest. That could change, according to a new study from the University of Illinois, which compared white mold strains from the U.S. and Brazil.

White mold has stayed in the upper U.S. for two primary reasons, the scientists noted. First, the U.S. strains require a period of cold, such as a winter, in order to produce the tiny spores that infect soybean flowers in the summer. Second, these spores operate best in cool conditions and favor 60-degree temperatures during the summer season.

The researchers were alarmed to discover that the Brazilian strains of white mold did not require a cold period to produce spores. If a strain from Brazil ever made its way to the U.S. -- or a U.S. strain mutated -- it's possible it could infect southern soybeans, the researchers concluded. However, the Brazilian strains did not like high summer temperatures any better than the American ones, which suggests these South American strains would not necessarily thrive in the southern U.S.

Nonetheless, the Illinois scientists urged southern growers to be on alert for the disease, noting that outbreaks have occurred as far south as Missouri and Kentucky. "If that happened once, can it keep going?" said University of Illinois crop scientist Glen Hartman in a university press release. "We don't know, but it's out there."

See the study here: http://bit.ly/… and the University of Illinois press release here: http://bit.ly/….

Emily Unglesbee can be reached at emily.unglesbee@dtn.com

Follow her on Twitter @Emily_Unglesbee

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Emily Unglesbee