is part of the Division of Informa PLC

This site is operated by a business or businesses owned by Informa PLC and all copyright resides with them. Informa PLC's registered office is 5 Howick Place, London SW1P 1WG. Registered in England and Wales. Number 8860726.

  • American Agriculturist
  • Beef Producer
  • Corn and Soybean Digest
  • Dakota Farmer
  • Delta Farm Press
  • Farm Futures
  • Farm Industry news
  • Indiana Prairie Farmer
  • Kansas Farmer
  • Michigan Farmer
  • Missouri Ruralist
  • Nebraska Farmer
  • Ohio Farmer
  • Prairie Farmer
  • Southeast Farm Press
  • Southwest Farm Press
  • The Farmer
  • Wallaces Farmer
  • Western Farm Press
  • Western Farmer Stockman
  • Wisconsin Agriculturist

Glyphosate vs. conventional chemicals

The National Agriculture Statistic Service (NASS) has said 1.7 million acres of cotton are in Mississippi. This was the first time since 1974 the state has planted that much, although Will McCarty, Extension cotton specialist, isn't sure about the NASS number.

“The boll weevil eradication effort folks say they can account for only 1.62 million acres, so there's a little discrepancy. The eradication effort deals with actual acreage while NASS works on estimates, so I'd tend to go with the 1.62 million acres,” says McCarty, who spoke at the Monsanto Center of Excellence Field Day in Yazoo City on Aug. 14.

Last week, NASS also released its crop forecast. NASS had Mississippi's cotton yield average at 747 pounds on 1.68 million acres.

“I think we have a really good chance of getting 700 pounds. I know we could average that if we could get rid of 400,000 acres of poorer cotton.”

The state started off the year really well. It was dry in some areas, but in the last week the state has gotten good rain almost everywhere. Although there are still a couple of areas “that can't buy a rain, we're still looking at a good crop. We have good fruit set, good vegetative growth.

“There has been a bit of concern about boll rot in the last few days. I received some calls on that and my comment is ‘I've never seen a sorry crop rot.’ Boll rot is something we have to accept. If you don't have boll rot, it's an indication that it's either hot and dry or there aren't any bolls in the bottom in the plants.”

The study

In 1997, quite a bit of Roundup Ready cotton was planted in Mississippi. McCarty says there were some very “significant” complaints about boll shed. He believes those complaints were linked to glyphosate application on that year's cotton.

As a result, research was begun and Monsanto made changes to its label — restrictions on how both over-the-top and post-directed spray applications should be made.

In 1998, McCarty again had a few complaints in Roundup Ready cotton. Most of those turned out to be bronze wilt or other physiological problems in the plant “not necessarily linked to gene technology.”

In 1999 and 2000, there were no complaints. In 2000, 87 percent of the state's acres was transgenic and over 50 percent of that was varieties with Roundup genes of some type.

“A couple of years ago, we geared up a project looking at Roundup Ready varieties planted in farmers' fields in large plots. At each location, we treated half the plot with Roundup over-the-top and directed spray. The other half we treated with no Roundup but conventional chemicals. We used no pre-emerge applications in the plots.

“In 1999, we looked at DPL 458 and DPL 1218 in Hinds, Coahoma, LeFlore, Bolivar and Yazoo counties. In 2000, we looked at DPL 458 and DPL 451 in the same locations.”

McCarty and colleagues mapped the plots and found no problems with fruit. There was a slight shift in where the fruit set, but there were no significant differences between the two systems.

In 1999, looking at total yield — “which is the bottom line” — there was no significant difference across the plots and systems. There was a slight numerical advantage to the glyphosate plots (930 pounds versus 920), but again nothing statistically different.

In 2000, with the exception of Bolivar County, the yields across all plots dipped. This demonstrates the brutal summer, says McCarty. Still, across all plots, there was no significant difference.

“Early on, we did notice a difference in growth. The Roundup-treated plots had no pre-emerge herbicide, and we saw more growth. This year, I've gotten some calls on boll shed — both in the bottom and middle parts of the plant.

“Typically, what you'll see with Roundup application made off-label or made too late is if sterility occurs, it'll occur two to three fruiting nodes above where the application is made. If there is a problem, a shed of sterile flowers usually happens in that area. There's usually not a plant with fruiting at the bottom, a gap in the plant and then cotton up top.

“What's induced some of this are over-the-top applications off label.”

In describing how to use Roundup Ready technology and glyphosate, McCarty often uses the analogy of a motorcycle. “A fellow told me as long as you remain a little scared of a motorcycle, it won't hurt you. But the day you think you know everything there is to riding one is the day you lose some skin.

“I think we're getting a little complacent with the application of glyphosate on cotton. The label is written with restrictions for a reason. This year, there are more growers on more acres. People got in a hurry, and there may have been some fuzzing on label applications. The last couple of years we've lost some fear or respect for glyphosate applications. It's simple: follow the label and you're much less likely to run into trouble.”


Hide comments


  • Allowed HTML tags: <em> <strong> <blockquote> <br> <p>

Plain text

  • No HTML tags allowed.
  • Web page addresses and e-mail addresses turn into links automatically.
  • Lines and paragraphs break automatically.