Volunteers and resistant weeds hitting US farming
2.Georgia: Pigweed threatens cotton industry
NOTE: Remember how GM crops were sold to farmers as making weed management simple and cost effective? Item 1 is from the blog of a UK agricultural journalist currently touring the States on a Nuffield scholarship; item 2 from a US farm publication.
EXTRACTS: [The problem of a lot of unwanted GM crop volunteers resistant to Roundup] is not unique to this field either most of the fields around here look like this. According to one chap I was talking to, he dug so many corn plants out of his fields that his soya yields were decimated. For some reason it's worse this year than it's ever been before. (item 1)
"It's been devastating in a lot of ways," said Stanley Culpepper, a weed specialist with the UGA College of Agricultural and Environmental Sciences who's taken a lead in fighting the [Roundup resistant] weed in Georgia. "We're talking survival, at least economically speaking, in some areas, because some growers aren't going to survive this." (item 2)
1.Any GM volunteers?
NufSaid, July 8 2010
I thought I'd use my unexpected rest stop at Champaign train station to catch up on a few blog posts. I'm swinging wildly from finding this escapade hilariously funny to getting really narked about my travel-related incompetency, so I don't know which tone these might take to reflect my mood. Apologies in advance if they got more sarcastic than usual.
Anyway, having heard nothing but how great GM crops are from certain Irish and Aussie know-it-alls, I thought I'd provide some balance from here in Illinois. Here's a picture of a soya bean field from behind my host's house:
I don't know if you can tell from the picture, but the dark green stuff is soya and the lighter stuff is corn. The farmers around here call it 'volunteer corn'. Basically it's Roundup-resistant stuff from last year that has set itself in this year's rotation of soya. Because it's GM it's resistant to any herbicide, so other than go and dig the plants out by hand, there's nothing the farmers can do.
It's not unique to this field either most of the fields around here look like this. According to one chap I was talking to, he dug so many corn plants out of his fields that his soya yields were decimated. For some reason it's worse this year than it's ever been before.
Interestingly he reckoned that weeds were starting to creep back into the fields too. It seems plants are starting to build up resistance against Roundup”¦
2.Pigweed threatens Georgia cotton industry
Brad Haire, University of Georgia
South East Farm Press, July 6 2010
*"We're talking survival, at least economically speaking, in some areas, because some growers aren't going to survive this." Several years ago, pigweed found the weakness and breached the defense that Georgia cotton growers used to control it. It now threatens to knock them out, or at least the ones who want to make money, says a University of Georgia weed expert.
"It's been devastating in a lot of ways," said Stanley Culpepper, a weed specialist with the UGA College of Agricultural and Environmental Sciences who's taken a lead in fighting the weed in Georgia. "It's without a doubt the largest pest-management problem that any of our agronomic growers are facing, especially our cotton producers."
If not killed early, pigweed - also called Palmer amaranth ”” can grow as tall as a small shade tree in fields, gobble nutrients away from cotton plants, steal yields and in severe cases make harvest difficult or impossible.
How did we get here?
In 1997, farmers started planting [GM] cotton that was developed to stay healthy when sprayed with glyphosate herbicide, commonly sold under the brand name Roundup. They could spray the herbicide over-the-top of this cotton, killing weeds like pigweed but not the cotton. Virtually all Georgia cotton grown now is "Roundup Ready" because it saves farmers time and money. But relying on one tool to do the job can lead to problems.
In 2005, the first case of pigweed resistant to glyphosate was confirmed in middle Georgia, the first confirmed case in the world. At the time, it was localized to a few fields on about 500 acres. The resistance has since spread across 52 counties, infesting more than 1 million acres. Within the next year or two, Culpepper said, it will likely be in every agronomic county in the state. It's also confirmed in most other Southeastern states.
Glyphosate didn't cause pigweed to change genetically or to become a resistant mutant, he said. All it took was a few weed plants in a field or area to be genetically different ”” in this case, resistant to glyphosate. The resistant ones survived to reproduce.
Pigweed is dioecious, meaning it needs separate male and female plants to reproduce. And it can reproduce a lot. The male produces the pollen. The female produces the seed. The resistant trait is passed through pollen, which can survive in the air and travel as far as a mile. One female plant can produce between 500,000 to 1 million seeds.
According to a survey last year, half of Georgia's 1 million acres of cotton was weeded by hand for pigweed, something not normally done, costing $11 million. Growers went from spending $25 per acre to control weeds in cotton a few years ago to spending $60 to $100 per acre now.
"We're talking survival, at least economically speaking, in some areas" Culpepper said, "because some growers aren't going to survive this."
Growers in middle Georgia who've battled the resistance for several years now are aggressively attacking the weed. Growers in other regions need to get on board. "If they don't have resistance yet they will," he said.
The key is diversity, or using more than one tool to fight invaders. Herbicides still provide good control, he said, but they must be applied at the right time and, if possible, under the right conditions. Growers, too, must reduce the number of pigweed seeds in their fields.
"Herbicides alone often will not provide adequate control. An integrated program must be developed to reduce the amount of Palmer that actually emerges," Culpepper said. "If it (pigweed) doesn’t come up, we don’t have to kill it."
Deeply tilling the soil in a field can reduce pigweed seed germination by as much as 50 percent in that field. Using heavy cover crops like rye to provide a thick mat between plant rows can also reduce germination by as much as 50 percent and give cotton plants a competitive edge over the weed. The combination of deep tillage and cover crops in a field can reduce pigweed seed germination by as much as 80 percent. All of this helps, he said, but it won't knock the giant out.
The situation is bleak, he said, but the cotton industry, chemical companies and researchers are responding and trying to catch up with pigweed.
"It won't be tomorrow or even next year, but we have some new technology coming. I'm certainly more optimistic. We've got some good options we’re testing now," Culpepper said. "But we're going to have to change how we've handled this pest in the past. If growers don't, they simply won't be growing cotton."