Ohio River Valley Growers Get Fast, Effective Control of Winter of Annuals

Search PMN

Greensboro, NC (April 6, 2006) - Heavy rains recently have delayed growers’ timetables for planting this spring. And the dense cover presents additional challenges when growers and their applicators get back into the fields to clear them out for planting. The prevalent weeds now are winter annuals such as chickweed, henbit and annual bluegrass.

“The dense cover is slow to dry out and warm up, leaving cold and wet ground,” explains Kentucky-based Sarah Gehant, Syngenta technical support representative for the Ohio River Valley. “In cool growing conditions such as we have now, the Gramoxone® brand has proven to control winter annuals very effectively and very quickly. A contact herbicide, our new formulation, Gramoxone Inteon™, kills weeds in as little as 24 hours. The unique speed of activity allows growers to more precisely control planting operations.”

Syngenta received registration for Gramoxone Inteon for the 2006 growing season. Gramoxone Inteon delivers broad-spectrum, non-selective control and proven efficacy on difficult-to-control weeds. It can be used alone or with a broad range of tankmix partners.

In addition, with the well-being of the user in mind, Gramoxone Inteon incorporates several one-of-a-kind features, including a milder alerting odor, an emetic, purgative and color alert.

Syngenta recommends application rates of 2.5 to 4 pints/acre, depending on weed height, when Gramoxone Inteon is applied as a preplant or pre-emergence burndown herbicide in corn or soybeans.

Preserve Glyphosate; Use Alternative Burndown

As an alternative burndown chemistry to glyphosate, Gramoxone Inteon helps delay the onset of weed resistance to glyphosate, when applicable.

Given that glyphosate-resistant weeds have infested approximately 3.3 million acres nationwide, proper weed management and glyphosate preservation are more important than ever. The same glyphosate-tolerant technology that has helped growers achieve higher yields and more efficient crop management has also encouraged glyphosate overuse, creating selection pressure that leads to glyphosate weed resistance.

“We recommend that when possible growers rotate chemistries, modes of action and crops in order to delay the onset of glyphosate weed resistance – whether you are planting glyphosate-tolerant or conventional crops,” says Gehant.

Apply Early

Gehant recommends saving glyphosate for where it will be most beneficial. “Use it over the top of glyphosate-tolerant soybeans and consider alternative burndown chemistries such as Gramoxone Inteon for both beans and corn.”

Glyphosate-resistant horseweed (marestail) continues to be an increasing problem in the Ohio River Valley states.

“One of the most important things we can do to control marestail is to spray it early,” says Philip Logsdon of Big Rivers Ag Supply, Owensboro, Kentucky. “Early applications fit well with using Gramoxone Inteon for burndown applications in combination with pre-emergence products.”

“Gramoxone Inteon is an effective treatment on glyphosate-resistant horseweed (marestail) early while the plant is in the rosette stage,” Gehant says. “When the marestail enters the bolting stage and the weed gets taller, growers will get a better result by switching to a glyphosate-based herbicide such as Touchdown®.”

Jim Martin, University of Kentucky weed scientist, recommends applying Gramoxone Inteon with 2,4-D.

“2,4-D ester is the preferred formulation, regardless of what else is in the mix. The key is to apply 2,4-D and a non-selective burndown pre-plant. Depending on rate of 2,4-D, you have a 7 to 30-day re-entry period so a later application will push your planting date much later than you’d want. If you use Gramoxone Inteon, use the high rate, 4 lb/acre and apply early, while the plant is in the rosette stage. When the plant gets bigger than that, performance gets inconsistent.”

If marestail plants are higher than 4 inches, Martin recommends FirstRate®, Sencor® or Canopy® in soybeans. He says “Canopy plus Gramoxone Inteon at the 4 pt/acre rate is a good program.” In corn, he says, “we use Gramoxone Inteon or glyphosate with atrazine and that combination controls the marestail.”

Bill Johnson, Purdue University weed scientist, and researchers from Purdue, University of Illinois, and Ohio State University, in a guide called “Biology and Management of Horseweed” echo Martin’s recommendations for horseweed control in soybeans.

Johnson and his colleagues recommend including 2,4-D ester in preplant herbicide treatments when possible, and applying before horseweed plants are 4 to 6 inches tall. The most effective treatment, they say, is “a combination of glyphosate and 2,4-D ester; plus chlorimuron or cloransulam (active ingredients in Canopy and FirstRate, respectively). They recommend Sencor, Gramoxone Inteon and 2,4-D ester for growers who want to use an alternative to glyphosate.

In corn, Johnson says, “glyphosate or Gramoxone Inteon tankmixed with atrazine or an atrazine premix is effective.” He offers some additional considerations:

• If any annual or perennial (johnsongrass or quackgrass) grasses are present and more than a couple of inches tall when the burndown applications should be made, glyphosate would probably be more effective than Gramoxone Inteon.

• If annual grasses are small, either product is effective.

• If dandelion or other perennial broadleaf weeds are present, add 2,4-D to the Gramoxone Inteon + atrazine premix mix.

Contact:

Mike Rubin

Gibbs & Soell, Inc.

mrubin@gibbs-soell.com

212-697-2600, x283