GMOs and Food

GMOs – The science and impact of the new technology

Is resistance and weed tolerance a problem today? In the future?

First Posted: 5:26 pm - September 16th, 2015 - Views

Story Tools:

Social Media:

By Gary Brock


COLUMBUS – What impact has the GMO had on the science and technology of farming? Just ask those who do the research and farmers in the field. They will tell you one of the biggest impacts has been the elimination of some of the historically destructive insects that had been – “had been” – a curse on corn farmers.

But there are two sides to the “science” of GMOs – genetically modified organisms.

Here is how Ohio State University entomologist Andy Michel describes how GMO corn has eliminated one pesky insect – the European Corn Borer:

“Part of my responsibility here is insect management, and this includes the use of and efficiency mostly in corn in Ohio of BT protection against insects. From the insect point of view, I think these have been very effective in controlling the insects they were meant to control.”

“BT” stands for the species of bacteria that the protein comes from: Bacillus thuringiensis (or Bt) is a Gram-positive, soil-dwelling bacterium, commonly used as a biological pesticide. It is a bacteria found naturally in soils.

“For example, the first one (GMOs) that came out, about 1996, was the European Corn Borer. There was a paper that came in 2010, the lead author was Bill Hutchison at the University of Minnesota, regarding a regional assessment of European corn boar population, after about 15 years of BT use against the corn borer. They could hardly find any. In Ohio, we can rarely find any corn borer, even in plants that are not BT. and for years and years, this was the most important pest we had. Now, with the use of BT, we have almost, not quite, but almost in corn have it to the point of extinction,” he said.

That has been a really good success story in form of BT crops. Across all of the Midwest, you will see there has been a major decline in European Corn borer, largely attributed to the rise of BT crops against it.

There is a flip side to this story. “In corn, BT use is almost a tale of two cities. In corn borer, it has worked fantastic. In root worm, not so much. The root worm genes came out in about 2003, and worked great for for the first six-seven years or so. But I am thinking about 2009, more so in 2010 and ever since in the Iowa Western corn belt, they started seeing heavy feeding and lodging on roots that were producing BT corn against root worms. Research found that many of the beetles collected in certain fields were surviving better on BT corn, suggesting that there was resistance to BT corn. In some fields, we saw complete failure of BT corn, which defeats the purpose of planting a BT variety,” he said.

Rotating seeds?

Why resistant? “The main idea we have, is that it seems that the areas of highest resistance to BT corn in Iowa and Nebraska was where there was a high concentration of continuous corn. It seemed after about three years of this, it seems that what you were doing was selecting beetles that were able to survive on BT corn. So after a time, what you were left with were beetles that could survive on that BT corn.

“We all know that farmers like their particular seed dealers, they like brand loyalty. In the early days of pesticides… what were farmers told? Rotate your chemicals. With the BT corn, this really wasn’t happening a lot. There was the brand loyalty and seed dealer down the street. So you had the same variety, the same BT corn year after year after year.

“So it is no surprise that you will have resistance to the root worms,” he said. So the resistance solution was to rotate seed varieties.

Michel said there is one other major difference between the root worm story and corn boar story. “In the corn boar, the traits were in something we call ‘high dose.’ Which meant it killed a lot of corn boar, very effective. With the root worm gene, it was not something considered high dose. But there was a lot more survival in root worms in BT corn than corn boars. The rates of survival were still very very low, less than 5 percent but it suggested that there was some genetic variation, a natural variation in the root worm populations that were natural selection for survival.

“In Ohio, we haven’t seen this resistant yet. We also don’t have as much continuous growth corn in the fields, either. There are a few, and these are high risk areas,” Michel said.


Michel was asked about the effectiveness of the GMO strain. “There is always monitoring that goes on to look at the effectiveness of the seeds, which is in the best interests of the companies and farmers. They want to make sure the product is performing. In corn borers, I don’t think there has been any reformulation of the products.”

Michel said the companies have difference genes, different toxins. Some companies are combining the toxins into the plant. “This could mean a plant produces three types of toxins against the European Corn Borer, which is good, because if a corn borer is resistant to one gene, it likely isn’t resident to another. You also decrease the chances of resistance.”

He does not know of any GMOs that create plant avoidance, that the insects don’t like the corn.

He said there is also a company that that has applied to the EPA to do trials of a product called “RNA Interference.” This is basically a gene-silencing approach and they hope to silence root worm genes instead of a bacterial toxin. It is a different approach that shuts down the rootworm’s genes and thus kills the larvae.

“However, I don’t think GMOs are a silver bullet and we have to be careful about how we use this variety. We can lose the durability, which can be argued has happened with root worm in the western corn belt. So need to be careful about how we use that. I know there are cases where it can be overused.”

Now that the European Corn Borer is gone, do we really need that gene in the plants? “Maybe not,” he answered. “A GMO is a tool that should be used when we need them to be used.”

Science and research

Ohio State entomologist Dr. Laura Lindsey was asked about GMOs and non-GMOs, and if there was a place for both in agriculture.

“As a researcher and scientist, I think both are good to have. There is a market for GMO food and market for non-GMO food. As a researcher and scientist we need both. A number of farmers can get a premium for growing non-GMO crops, so there is a financial incentive for them. So that is completely justified. But there are a lot of benefits to GMO crops,” she said.

“I do research on both GMO and non-GMO crops and they are both interesting. I hope there is a future for both.”

“Roundup Ready”

What does “Roundup Ready” mean in relation to GMOs? “These are genetically modified plants to be herbicide tolerant. So if the plant is “Roundup Ready” you can spray Roundup in the field to kill weeds but the plants do not die. Roundup herbicide is a broad spectrum, so it pretty much kills anything. So if you spray Roundup in a field that is not GMO Roundup tolerant the weeds and the plants would die. There are other herbicide sprays you can use, not just Roundup,” she pointed out.

The downside? Potential weed resistance issues. “If farmers spray Roundup year after year after year in a corn and soybean rotation and don’t use other herbicides or modes of actions, then they put selection pressures on their field. Some of those weeds may be resistant to Roundup and make it ineffective,” Dr. Lindsey said.

“The herbicide doesn’t really change the weed. It is more of a selection pressure. If you use the same product over and over you are selecting for weeds that – since there are a lot of bio-types in weeds and some may be naturally resistant – you are allowing for this. Weeds can produce a lot of seeds, hundreds of thousands. Eventually you are building up a population of weeds that are resistant,” she explained.

“This is not just a GMO issue, it is a good pest management issue. This can happen with non-GMO crops also if you spray the same type year after year,” she added.

A deceptive science?

Amalie Lipstreu, Policy Program Coordinator for the Ohio Ecological Food and Farm Association, has a different perspective on science and GMOs.

“One of the arguments made frequently is that the public just doesn’t understand the science, and if they only understood the science then they would not mind the use of this technology in their food. But I think that there are concernswhen you talk about the science,” she said.

“Number one, a lot of the science is industry sponsored science. The goals of a company is to maximize value for for their shareholders. I am not saying that they are not concerned about the public or public health, but that is not their key concern, right? To totally rely on industry-sponsored science is a little like putting the fox in charge of the henhouse,” she said.

One of the claims by GMO proponents is the need to increase yield to “feed the world” and that GMOs have reduced chemical usage, but she said Dr. Gerian Sherman’s “Failure to Yield” 20-year study on intrinsic yield showed that in some categories there was not a substantial increase in yield, Lipstreu said.

“We don’t want to put all of our eggs in one basket. We don’t want to abandon traditional methods of seed breeding and hybridization. That is an important tool for us.” She said his study showed that chemical usage had not decreased and in fact herbicide use has increased.

“We see the real result of that now with the herbicide resistant weeds,” she added.

“We now have 12-15 resistant weeds around the country that have evolved to resist chemical. The response has been to develop Enlist 2 with the herbicide that don’t affect the crops. It is sort of the definition of insanity. We keep doing the same thing and expected a different result. We are going to use a new chemical combination, so how many years will it take for these weeds to be resistant to this chemical? So then we develop an even more toxic chemical. We don’t want to be on a chemical treadmill all the time,” Lipstreu said.

Gary Brock can be reached at 937-556-5759 or on Twitter at GBrock4.

Is resistance and weed tolerance a problem today? In the future?
Rural Life Today