Corn and weeds coming up in a hurry

Mid-South farmers had high hopes for their corn crops this year, what with good prices and a very promising start to the season.

Acreage had jumped from 550,000 acres to 789,000 acres in Tennessee, from 340,000 acres to 950,000 acres in Mississippi, from 300,000 acres to 700,000 acres in Louisiana and from 190,000 acres to 560,000 acres in Arkansas.

The season so far has been near perfect for some and a near disaster for others.

A killer Easter freeze, followed by a several days of cool weather, struck thousands of acres in the northern part of the Mid-South. An estimated 500,000 acres of Mid-South corn had to be replanted.

When the weather finally warmed up in the upper Mid-South, corn producers went into scramble mode. The first problem for west Tennessee corn producers, finding Roundup Ready replanting seed, was solved when some Midwest producers decided to back off corn acreage, freeing up the seed for the Mid-South.

The second problem was killing Roundup Ready corn still alive from the original planting. In west Tennessee, the recommended option was 40 ounces of Gramoxone Inteon and 3 ounces of Sencor. “It did a fabulous job, but we ran out of Sencor,” said University of Tennessee weed specialist Larry Steckel. “We had a lot of growers in west Tennessee use Gramoxone and Direx. Some used straight Gramoxone.

“As beat up as the corn was though, it turned out that just about anything would kill it. I’m not convinced that would always be the case, but it was struggling so much that all it needed was a little push.”

Tennessee received a crisis exemption for Select herbicide, which was used to kill the old standing plants. “But by the time we got it, it was almost too late, the corn was pretty much replanted.”

The third problem was that replanting put many producers behind on cotton planting and weed control in corn. “Replanting has really thrown a wrench into everything,” Steckel said. “Our pre-emergence herbicides are really running out of gas right now, and we’re getting some weed flushes. In many cases, we are at or near the ceiling for how much atrazine we can use.”

If you’re close to the limit on atrazine applications, “a herbicide to consider as a kind of atrazine replacement is Callisto,” Steckel said. “It’s really good on the broadleaf weeds and has good grass activity, and you can spray it on up to 30-inch corn.”

Weed flushes seen in the first two weeks of May include Palmer pigweed and annual grasses like broadleaf signalgrass and mornningglory. “Fortunately, a lot of our corn is Roundup Ready corn, so we can go out with a shot of Roundup for the next week or so before we hit the ceiling on being too tall.”

However, if producers do not include a residual with Roundup, “we could see some terrible weed messes come harvest time.”

Producers have also seen flushes of resistant horseweed, noted Steckel. “Roundup is not going to control it, and a pint, or even a quart, of atrazine isn’t going to control it in many cases, either. A lot of farmers are looking at dicamba in a tank mix with Roundup. In most cases, it should work pretty well for them.”

Steckel notes that on occasion after a dicamba application, when conditions are optimal for corn plant growth, “you can see corn start to lean and for several days be tender to a wind. It happens when you have very good growing conditions and you’ve put out a growth-regulating herbicide.”

Steckel noted that corn is close to the 12-inch cutoff for a many herbicides such as Steadfast and atrazine. “Getting a herbicide application on all the corn is going to be impossible in a lot of cases, especially since a lot of producers are planting cotton now.

“In that situation, corn producers will have to go back later with herbicides that they can put on up to 30-inches, like the dicambas, Callisto, Roundup or Liberty in LibertyLink corn. But typically, they can be more costly and producers are going to have more weed competition until then.

“If it stays dry, yields could be reduced in weedy fields,” says Steckel. “From about knee-high on, that’s a critical time in the corn plant’s life. The number of rows of kernels is being determined. Stress is not good. Early on, you can have a few weeds and it’s no big deal.”

Steckel says around 200,000 acres of corn were replanted in the west Tennessee area, a figure similar to acreage replanted by Missouri and Arkansas corn producers.

David Lanclos, LSU AgCenter soybean and feed grain specialist, says Louisiana corn producers “have done an exceptional job. I am very optimistic about this crop.

“A few farms are too wet and a few others are too dry. However, we have had adequate rainfall and at this point (May 10) we are five or six days away from an irrigation. We’re saving a tremendous amount of money at this time by not having to initiate center pivot or furrow irrigation. That’s good news considering the costs that went into the crop.

“The biggest problem that Louisiana growers are facing has been lack of weed control. Growers whose fields were too wet slipped into the field a little too late, and we are going to have some yield losses from that. Some of our fields are very weedy and no amount of herbicide will get that yield back.”

Insect pressure has been very light, according to Lanclos. “Stink bug pressure has been very light and I had one report today of a corn borer being found in milo.”

Lanclos does not recommend spraying a fungicide on corn, “but we do encourage farmers to try it. But leave a check to see if you have an effect with it. We have only limited data from Louisiana, Mississippi and Arkansas. We feel that something is there (regarding the benefit of a fungicide), but we don’t have a good enough handle on it yet to make a recommendation.

“We’re going to need a couple more years of data. If fungicides are the next big thing in corn, you can bet we’ll be behind it 100 percent. But there are a lot of details we need to figure out too.”

Lanclos is also concerned that an abundant harvest could have an adverse impact on storage and transportation. But a staggered planting season may have been a blessing in disguise.

“I don’t think we could have had a better planting season. I’m not so much worried about combine capacity. I’m more worried about trucks moving the corn from the field to the elevators. I’m confident the elevators are going to stay open long enough to get to the trucks. There will be lines, but if we can get the rails moving and the barges moving, my skepticism is the trucks. We need more of them and we need diesel less than $3 a gallon.”

e-mail: [email protected]

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.