New herbicides added to your weed control kit
Weed control systems expanded for 2010 if you’re using Roundup Ready or LibertyLink hybrids. Several new options are designed to help improve overall weed control in these systems.
“Most of the new products are most useful in a system that includes a postemergence broad-spectrum herbicide in corn,” says Tom Bauman, Purdue University weed control specialist.
Bauman and fellow Extension specialists Bill Johnson, Tom Jordan and Glenn Nice recently outlined what’s new in herbicide options for 2010.
• Corvus. This product is labeled for soil-applied preemergence and early post applications in corn. The upper limit is V2 corn. Made by Bayer, its active ingredients include isoxaflutole (Balance) plus thiencarbazone methyl, plus a safener.
Adding atrazine helps performance, especially on ragweed, cocklebur and morningglory, Johnson says. “You’re trying to gain whatever suppression you need early. That helps preserve yield versus letting weeds get ahead of you before you make the postemergence glyphosate application.”
• Most new herbicides work best with glyphosate or glufosinate.
• BASF adds three herbicides with Kixor technology.
• Labeled rate not always same as earlier experimental rate.
• Sharpen. This is one of three new offerings from BASF. All contain Kixor technology. The active ingredient is new chemistry — salfufenacil plus a safener. It’s a preplant burndown and preemergence product for both corn and soybeans. Apply at 2 to 3 ounces per acre in corn and 1 ounce per acre in soybeans. At the labeled soybean rate, it suppresses broadleaf weeds and should be used with a residual broadleaf herbicide.
“We see a real fit in helping on marestail,” Johnson says. “It can take out emerged marestail up to a foot tall in three days. However, the low use rate in soybeans will limit residual control on marestail.”
It can be used with glyphosate in place of 2,4-D ahead of soybeans in a burndown mix. This combination won’t have a seven-day plant-back restriction, Johnson observes.
• Optill. Also from BASF, Optill’s active ingredients are salfufenacil plus imazethapyr, the active ingredient in Pursuit. It’s preemergence for soybeans.
Any new products containing salfufenacil can’t be applied within 30 days of certain herbicides, including Authority First, Sonic, Authority Assist, Authority MTZ, Prefix, Valor, Valor XLT, Envive and Gangster.
• Integrity. This is the third new offering from BASF. It contains salfufenacil plus dimethenamid, the active ingredient in Outlook. Use it preemergence in corn. Labeled rate is 10 to 16 ounces per acre. “It appears to be a very good herbicide,” Johnson notes. He’s looked at it in trials for several seasons.
The only caution is that Johnson looked mostly at experimental rates of 20 to 25 ounces per acre. He has less experience at the current labeled rate.
• Prequel. It’s a soil-applied herbicide from DuPont, intended for pre-plus-post herbicide programs in corn. Active ingredients are isoxaflutole, plus rimsulfuron. It provides early-season, residual control of grass and broadleaf weeds.
Prequel also controls small, emerged weeds, up to 3 inches tall, in no-till. Adding atrazine, glyphosate or 2,4-D improves preplant burndown results.
• Flexstar GT. Syngenta offers a premix of Flexstar plus glyphosate for postemergence use in Roundup Ready soybeans. The active ingredient in Flexstar is fomesafen. Maximum rates vary. Read labels carefully. Spray at 15 to 20 gallons per acre with flat fan nozzles. Add crop oil concentrate, MSO or AMS for glyphosate-resistant weeds.
PERPLEXING PUZZLE: How do you remove herbicide-tolerant volunteer corn in continuous corn? Bill Johnson wants to find out.
LOOK AND COMPARE: Dave Smith likes to visit weed trials to see results firsthand. He’s the Extension ag educator in Johnson County.
This article published in the February, 2010 edition of INDIANA PRAIRIE FARMER.
All rights reserved. Copyright Farm Progress Cos. 2010.