Timing, Product Choice Important For Postemergence Herbicide Applications

Weather has prevented Indiana corn farmers from applying herbicides before much of the crop emerged from the ground. But that doesn’t mean it’s too late, a pair of Purdue Extension weed scientists say.

Most of Indiana’s corn crop was planted May 4-9, but windy conditions followed by days of rain kept growers from applying pre-emergence herbicides for weed control. The good news, however, is that many of these herbicides are still safe for farmers to use after corn has emerged so long as they pay close attention to product selection and application timing, Bill Johnson and Travis Legleiter said.

“Many of the pre-emerge herbicides can also be applied post-emerge, and there are many herbicides for postemergence weed control in corn,” Johnson said. “The large number of products is a positive when considering glyphosate-resistance management and prevention, but they can also make timing and product application decisions more complicated.”

This is especially true because postemergence herbicides can affect corn ear development if those products are applied too late in the growing season.

When growers decide on herbicide products, Legleiter said they should consider weed species present, weed height and crop growth stage.

“The majority of conventional post-applied corn herbicides are effective on select weed species and only at certain weed heights,” he said. “Typically, a combination of products or a prepackage of active ingredients is needed to achieve control of all weed species present.”

Herbicide labels are a valuable resource for growers because they list which weed species the products control and recommended application heights.

Another resource is the Indiana and Ohio Weed Control Guide, published by Purdue Extension and Ohio State University Extension. The guide is available for free download from Purdue Extension’s The Education Store and searching for product code WS-15-W.

In addition to product choice and application timing as it relates to weed height, Johnson said it’s extremely important for growers to consider the growth stage and height of corn at the time of herbicide application to prevent injury.

“The type and amount of injury from an application beyond the labeled window is dependent upon the herbicide, other environmental stresses and the exact timing of application,” he said.

Injury symptoms can include ear pinching, ear bottlenecking, internode stacking, onion leafing, rat tailing, brace root malformation and green snap.

  • Johnson and Legleiter also offered a list of helpful tips for avoiding herbicide crop injury:
  • Don’t use contact herbicides right before rain or when there is heavy dew in order to avoid washing the herbicide down into the corn whorl.
  • Don’t apply growth regulator herbicides after several nights with temperatures 45 degrees Fahrenheit or cooler.
  • Don’t use UAN solutions as the herbicide carrier when applying atrazine premixes to spike-stage corn.
  • Don’t mix growth regulator herbicides with chloroacetamide herbicides and apply postemergence.
  • Don’t apply ALS inhibitors past the V6 growth stage in corn.
Topics:

Leave a Reply

Crop Inputs Stories

FertilizerGypsum Added To List Of Conservation Practices
July 28, 2016
Crop farmers in a growing number of states may be eligible for financial assistance from the USDA’s Natural Resources Conservation Read More
Palmer pigweed seedhead in cotton
HerbicidesStudy: Fall Weed Controls Can Make Significant Impact On Glyphosate-Resistant Palmer Amaranth
July 28, 2016
An article published in the latest issue of the journal Weed Science shows that adopting harvest-time and post-harvest weed controls Read More
InsecticidesSyngenta: Beware Of Early Stinkbug Threat To Soybeans
July 28, 2016
With the record warm temperatures this past winter and confirmations from early entomologist reports, Syngenta encourages growers to monitor stinkbug Read More
Peanut field
Crop InputsVerdesian Introduces New Inoculant For Peanuts
July 28, 2016
As planning begins for the next growing season, Verdesian Life Sciences adds Primo Power CL, a new liquid inoculant, to Read More
Trending Articles
Southeast Farmers Coop - Finished Building
Retail FacilitiesNew Stueve Facilities Offer Ag Retailers Speed, Accuracy
July 9, 2016
Leading the industry in planning and constructing dry fertilizer storage and chemical warehouse solutions, Stueve Construction helped three ag retailers Read More
Heritage Cooperative
Retail FacilitiesKahler Automation Designs State-Of-The-Art Facility For Heritage Cooperative
July 4, 2016
Heritage Cooperative in Marysville, OH, needed an efficient liquid, dry and grain facility to serve the many needs of their Read More
The Andersons Waterloo
ManagementFirst Indiana Facility Certified Under 4R Nutrient Stewardship Certification Program
June 27, 2016
The 4R Nutrient Stewardship Certification Program has announced that The Andersons, Inc.’s Waterloo, IN, facility has been added to its Read More
Food IT
Industry NewsCalifornia Event Will Mix Ag And Tech Professionals To Explore IT Solutions
June 20, 2016
Silicon Valley is hot on agriculture, and an upcoming event in California will bring together the food and tech industries Read More
Monsanto Luling Plant
Eric SfiligojWhat’s Next For Monsanto?
May 31, 2016
For the folks at Monsanto’s headquarters in St. Louis, MO, it has been an eventful few weeks. Back on May Read More
Soybean Plant closeup
Industry NewsMonsanto Rejects Bayer Bid; Open To More Talks
May 25, 2016
Monsanto Co, the world’s largest seed company, turned down Bayer AG’s $62 billion acquisition bid as “incomplete and financially inadequate” Read More
Latest News
FertilizerGypsum Added To List Of Conservation Practices
July 28, 2016
Crop farmers in a growing number of states may be eligible for financial assistance from the USDA’s Natural Resources Conservation Read More
Management2016 CTIC Cover Crop Survey: 33% Report ROI From Cover …
July 28, 2016
Insight from 2,020 farmers from across the country reflected enthusiasm for cover crops and—for the fourth year in a row—found Read More
Palmer pigweed seedhead in cotton
HerbicidesStudy: Fall Weed Controls Can Make Significant Impact O…
July 28, 2016
An article published in the latest issue of the journal Weed Science shows that adopting harvest-time and post-harvest weed controls Read More
InsecticidesSyngenta: Beware Of Early Stinkbug Threat To Soybeans
July 28, 2016
With the record warm temperatures this past winter and confirmations from early entomologist reports, Syngenta encourages growers to monitor stinkbug Read More
Peanut field
Crop InputsVerdesian Introduces New Inoculant For Peanuts
July 28, 2016
As planning begins for the next growing season, Verdesian Life Sciences adds Primo Power CL, a new liquid inoculant, to Read More
Soil Young Corn
Crop InputsSmithsonian: 5 Things to Know About New GMO Labeling Bi…
July 27, 2016
On July 14, the House of Representatives passed a bill requiring large food companies to label products containing genetically modified Read More
Palmer pigweed in soybean stubble
HerbicidesSpecial Issue Of Weed Science Explores Human Aspects Of…
July 27, 2016
Weeds that evolve resistance to herbicides are a serious threat to global agricultural production. In this Special Issue of Weed Science, Read More
CHS Primeland
CropLife 100CHS Businesses In Washington, Idaho Combining For Great…
July 27, 2016
As full-service ag retailers, CHS Primeland and CHS Farmers Co-op collectively serve farmers and other customers in 15 counties in Read More
Storage Tanks at Nachurs
Crop InputsNACHURS Joins Field to Market
July 27, 2016
NACHURS announced today that it has joined Field to Market: The Alliance for Sustainable Agriculture, a leading multi-stakeholder initiative working Read More
Illinois Researchers
FertilizerMeasure Of Age In Soil Nitrogen Could Help Precision Ag…
July 26, 2016
What’s good for crops is not always good for the environment. Nitrogen, a key nutrient for plants, can cause problems Read More
Kochia
Crop InputsNufarm Launches New Herbicide for Resistant Kochia
July 25, 2016
Nufarm introduces Scorch herbicide for U.S. farmers and ranchers combating a broad range of troublesome broadleaf weeds. A unique premix Read More
ManagementNew Rabobank Report Calls for Farmer ROI Focus
July 25, 2016
As U.S. row crop farmers brace themselves for a third year of negative margins, Rabobank believes farmers must lower the Read More
Syngenta Sign
Crop InputsBloomberg: Syngenta-Chem China Deal on Track for Regula…
July 25, 2016
Syngenta AG, which has agreed to be taken over by China National Chemical Corp. for $43 billion, said talks with Read More
ManagementGROWMARK Meeting Visit, Company Takeover Updates, and R…
July 22, 2016
Editors Paul Schrimpf and Eric Sfiligoj discuss their recent speaking engagement at GROWMARK’s eastern event, crop protection company merger rumors, Read More
Crop InputsMonsanto: EU Approves Roundup Ready 2 Xtend Imports
July 22, 2016
Monsanto Co. announced today that the European Commission has granted import approval for Roundup Ready 2 Xtend soybeans. This milestone Read More
Syngenta headquarters in Basel, Switzerland
Crop InputsSyngenta Announces Alfalfa Seed Split Off
July 22, 2016
On September 1, 2016, Syngenta will transfer sales and distribution of alfalfa seed to the NEXGROW branded business that is Read More
Dow DuPont
Crop InputsDuPont, Dow Shareholders Approve Merger
July 21, 2016
DuPont and The Dow Chemical Company announced that, at their respective special meetings of stockholders held today, stockholders of both Read More
ManagementLand O’Lakes Announces SUSTAIN Business Unit, Oth…
July 20, 2016
Land O’Lakes, Inc. today announced the formal organization of a new business unit, SUSTAIN, and its leadership. SUSTAIN will focus Read More