FORT WAYNE — Weed-free rows of corn and soybeans are becoming harder for local farmers to achieve due to growing plant resistance to herbicide. That’s why the local ag industry is watching the possible deregulation of genetically-modified seeds.
The United States Department of Agriculture is taking public comments on the proposed approval of modified corn and soybean seeds that would resist the herbicide 2-4, D. Dow Agri Science has asked for approval to release such seeds to the market, some of which have been test-grown in Elkhart County. Test seeds are destroyed and not marketed.
The genetically-modified seeds would allow farmers to spray the 2-4, D herbicide over the top of corn and soybeans to kill weeds that have become resistant to the popular glyphosate products.
“What has happened,” said Rod King of Goshen, an agronomist with Brodbeck Seeds, a subsidiary of Dow Agri Science, “is over time we have a few populations of weeds that are becoming resistant to Roundup. So that system that used to be the most failsafe, isn’t anymore.”
Roundup is Monsanto’s trade name for glyphosate, a herbicide developed in the 1970s, and used extensively by farmers worldwide to control weeds. The herbicide was so effective it changed farming. Farmers used to till their field to bury weeds before planting, but Roundup allowed farmers to go to no-till farming, which prevented soil erosion from wind and rain.
“2-4, D is going to help us greatly, particularly on some of the weeds that have become resistant to Roundup,” King said. “So, I wouldn’t say it is an alternative to Roundup. I would say it’s a companion to the Roundup system.”
According to King, Dow’s genetically-modified seeds will be marketed under the Enlist brand.
Genetically-modified seeds are nothing new. Most soybeans and corn planted in the United States have had a gene-splice to make them resistant to Roundup, according to The Associated Press. But many Americans don’t like the idea of gene-splices in seeds and the issue has become political.
The most troubling weed to local farmers is mare’s tail, according to farmers and ag industry representatives attending the annual Fort Wayne Farm Show last week. But an even more prolific weed has arrived in Elkhart County from the South, where it is creating economic hardship for cotton farmers.
“Here’s the next one that is going to be a son of a gun to handle,” said Bob Mayo, an agronomist with Seed Consultants Inc. of Washington Courthouse, Ohio, as he reached out at his company’s show booth with a flier about Palmer’s amaranth.
The Palmer plant, as farmers know it, was once cultivated by Native Americans in the Southwest for food. But it has found modern ag practices favorable for spreading and is well-established in the Southeast and is moving north.
According to Mayo, the plant arrived in Northern states through the use of cotton seed hulls by dairy farmers. Cotton seed hulls are added to dairy feed because they provide nutrition and amaranth grows in cotton fields. The problem for Elkhart County farmers is Palmer’s amaranth became resistant to Roundup in the South and is now taking over cotton fields there. And farmers are worried the same economic disaster may occur in the Corn Belt.
“We found it this summer,” said Jeff Burbrink of the Elkhart County Purdue Extension Service. “It’s here. We found it in several different places.”
Palmer’s amaranth is a prolific breeder, according the Burbrink, because it has both a male and female plant and can produce up to 500,000 seeds per plant. And because it produces easily and quickly through two parents, it has an evolutionary advantage.
“Because the plant has male and female it means it can change up its genetic makeup pretty quickly,” he said. “...A plant that survives a dose of product (such as Roundup) and builds up a resistance to that product can pass that resistance pretty quickly.”
A worry of Burbrink’s is that creating seeds that are resistant to 2-4, D may not end the threat from Palmer’s amaranth because farmers may try to use just 2-4, D on crops the same way they relied mostly on Roundup in the past.
“We have got Palmer problems around the South because that type of program was so easy to do,” Burbrink said of relying on Roundup to control weeds. “For 10 or 15 years you could drive around here and the bean fields had been extremely clean because we had the ability to go over them with one or two passes of Roundup and make them awesomely clean.”
Roundup attacks plants by limiting a critical amino acid, Burbrink said, which is just one of nine ways to attack plants with herbicides.
“The same thing can happen if you apply the same herbicide over and over. You need to mix up those herbicides,” he said.
Mayo also tells his customers to mix up the type of herbicides they use.
“What we look at is mode of action, which is how weed control works on plants,” Mayo said. “Some of them work by starving the plant, by causing de-photosynthasis, and others kill them when they are young. There are nine modes of actions, so you have to use multiple modes, from pre-plant to in-crop, to using some control in the fall.
“To be a farmer today, you have to be on top of your weed control knowledge and what you have on your farm,” Mayo said.
And prevention of the Palmer’s amaranth problem may be pretty simple for some farmers.
“I went around to all my dairy guys and told them what is coming. I told them it is probably easier not to use cotton seed than to correct the problems that come with it,” Mayo said.
Some of those who have opposed the use of 2-4, D are other farmers, according to King.
“It can be nasty on tomatoes, for example,” he said.
But Dow has reformulated 2-4,D to make it less volatile, which means it is less likely to drift on slight winds into non-targeted ag plots, according to King. The new formula will also resist volatilization due to changes in temperatures, which can allow the existing 2-4,D formula to vaporize a day after it is applied and drift off-site.
“We think the non-target issues are going to be very, very minimal,” King said.
If approved, the new seeds could be on the market as soon as 2015, according to King.
The new 2-4, D formula, coupled with the genetically-modified seeds, will allow farmers to spray the new 2-4, D over the top of corn at any point in its growth to kill weeds that may have germinated after an initial spraying of another herbicide, King said.
Weeds in a small vegetable garden can be controlled through hoeing or back-breaking hand pulling. But scale that effort up to hundreds or thousands of acres of corn or soybeans, and manual labor is not an option, according to those in the ag industry at the Fort Wayne show.
So the application of herbicides is used to control weeds. And what would happen if weeds were not controlled by herbicides?
“Our yields would decline dramatically, said Brian Mitchem, an agronomist with DuPont in Decatur, Ind. “It gets back to the old issue — we are adding 40,000 new people on this planet every single day. Every one of them is hungry and they all have to be fed. So we have to continually increase the amount of calories and protein we produce in order to feed the population. And if we don’t, you simply would have even more people who were malnourished and starving.”