Yes, growers use Bt corn hybrids, but refuge compliance still confusing


URBANA, Ill. — More than 90 percent of participants in the 2011 Corn and Soybean Classics said they planted transgenic (Bt) corn in 2010, and 94 percent plan to plant it in 2011. However, refuge confusion and compliance remain key concerns for producers this growing season.

Since 2000, the use of Bt corn has increased at a very steady rate and has become the dominant production input fundamentally reshaping the manner in which producers manage insects and weeds, said University of Illinois Extension entomologist Mike Gray.

Unlikely to change

“Although seed prices, along with other input costs, have risen steadily during this time frame, and remain a concern of producers, the current favorable commodity prices will continue to fuel the reliance on transgenic crops for the foreseeable future,” he said.

“Unless widespread resistance to Bt corn by an insect pest develops, demand should remain high for transgenic hybrids that increasingly offer broad-spectrum protection against lepidopteran pests and corn rootworms.”

The use of so-called “stacked” Bt corn hybrids has increased significantly since 2006 in the United States, reaching 47 percent of planted corn acres in 2010. However, the percentage of corn acres planted to stacked hybrids decreased by 7 percent from 2009 to 2010 for Illinois.

Gray believes reasons for the decline are related to low pest pressure the past few seasons and concerns over rising seed costs.

“I suspect the decline in use of stacked Bt hybrids observed in Illinois during 2010 will eventually be reversed and the use of pyramided Bt products will become dominant in the marketplace,” he said.

Stacked vs. pyramided

To be clear, Gray points out there is a difference between the terms “stacked” and “pyramided.”

According to the U.S. EPA, pyramided Bt hybrids are products containing two or more toxins efficacious against the same pest. The toxins (Cry proteins) should have distinct, non-cross reacting modes of action.

On the other hand, stacked Bt hybrids are products combining toxins efficacious against different pests.

Decreasing numbers of European corn borers are directly related to increased use of Bt hybrids. For example, during the past two years, western corn rootworm densities also have been low across Illinois.

Gray said three factors are responsible for this trend, including saturated soils at the time of larval hatch, increased use of Bt hybrids, and widespread applications of pyrethroid insecticides tankmixed with fungicides used on corn and soybean acres in recent growing seasons.

All three factors have resulted in a population suppression of western corn rootworms and have left many entomologists wondering if densities of this once perennial pest will rebound in the near future.

Refuge is critical

“Due to the diversity of Bt hybrids and differing refuge requirements, there is concern that refuge compliance will continue to erode as confusion and ambivalence increases,” Gray cautioned.

At the 2011 Corn and Soybean Classics, slightly more than 20 percent of producers indicated they did not establish a refuge according to the recommended guidelines.

“As refuge compliance decreases, we should anticipate increasing selection pressure on pest populations and their eventual adaptation to Bt hybrids.”

Gray said this would be a significant loss and helps explain why the U.S. EPA is interested in moving forward with the use of seed mixtures as a refuge strategy for some Bt products.

In 2011, the dominant resistant management strategy will continue to be the 20 percent structured refuge approach for most Bt hybrids. On average, nearly 66 percent of producers at the 2011 Corn and Soybean Classics indicated they will use this refuge deployment with their Bt hybrids.


As more pyramided Bt hybrids enter the market, the use of the “refuge-in-a-bag” approach will become the dominant refuge management practice, Gray said.

“In essence, we will see a 95 percent to 5 percent agricultural landscape emerge with Bt and non-Bt seed interspersed in cornfields,” he said.

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  1. We have stacked traits again this year, but here in NW Indiana we haven’t had the insect pressure for a few years either. Our seed reps do a very good job of making sure our refuge products are in with our orders for stacked seed. Everyone needs to do their part to keep the technology viable.

  2. In this story the seeds are being called hybrids, that would be incorrect. They are Genetically Modified Organisms (GMO’s). These plants do not exist in nature nor could they be created through traditional hybridizing techniques. These plants, bt corn, have been created in a laboratory by physically inserting the DNA from BT bacteria and to make the corn DNA accept its new alien genes they also insert the DNA from the deadly E Coli bacteria, and to make the DNA traceable they have added a touch of antibiotic genes as well. If this corn is also roundup ready another bit of DNA from a plant that is resistant to roundup has been added as well. So you see, this corn is not a hybrid, it is the product of a laboratory experiment.
    Now you feed this corn to livestock and wonder why there is ecoli in the meat, or wonder why the illnesses livestock might contract are becoming resistant to antibiotics. The GMO corn is also unhealthy for livestock, causing organ damage that takes time to build up. You wonder why super weeds are growing. It was built right into the seeds, the corn, the soy.
    GMO corn is also cross pollinating with “real” corn. One problem with these cross breeds is that because of the trace ablity Monsanto can sue the the poor farmer that tries to save, sell or use the seeds from his own corn which he thought was regular open pollinated corn.
    And Organic farmers that have been cross pollinated by GMO corn will loss their organic certification when it is found in their corn. And of course you have to already know that if you are planting roundup ready corn and spraying you are only adding to the problem of super weeds. One more thing, anyone planting monsanto seed is supposed to sign a contract or waiver, have you read this thing? you better. monsanto make sure that when the organic farmers come to sue for loss of lively hood that they are off the hook and you as the GMO farmer are held liable, yes it will be all your fault that organic farms go under and you are the one who will be sued out of house and home.
    Don’t believe me?
    Look it up.

  3. Even worse then. I just hope the farmers understand or at least research how bad GMO corn, soy and now alfalfa is for human health, the environment and for the organic farmers, and how their decision to plant GMO crops will impact the future.


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