8 Tips For Controlling Weeds Postharvest

Have you struggled with winter annual weeds getting in the way of spring planting? Many farmers are fighting off these weeds with fall herbicide applications. Applying a herbicide now may help you save time next spring, said Aaron Hager, University of Illinois Extension weed specialist.

Before making a fall herbicide application, Hager offers a few reminders:

1. Scout fields before making any application. This helps determine what weeds are present and if their densities are high enough to warrant treatment.

2. Many herbicides used prior to or after crop planting/emergence can be applied in the fall, but not all herbicides are labeled for fall application.
Atrazine, for example, is widely used before and after corn emergence, but is not labeled for fall application. Check the label to determine if fall application is allowed.

3. Some herbicides approved for fall application have application timing restrictions on their labels. If you are considering applying a treatment (such as glyphosate) that does not possess much soil-residual activity, the application should be timed to occur after the majority of winter annual species have emerged. Instead of applying such a treatment in early-October, a mid- to late October application timing might provide better results. If your fall application will include a herbicide with soil-residual activity, then the application could be made sooner, but check the product label.

4. Combinations of one or more herbicides can broaden the weed control spectrum. This can be very important if winter annuals have already emerged before the application is made. Combining 2,4-D and/or glyphosate with soil-residual products can improve control of emerged species and help control biennial or perennial species. Include the appropriate spray additives with all applications.

5. Location in the state can influence fall herbicide applications. Fall herbicide applications seem to “fit” better in areas of central and southern Illinois. Labels may indicate fall applications that can be made only in certain geographical regions of the state.

6. Fall applications that include soil-residual herbicides may not always result in a clean field by planting time next spring.
Delays in spring fieldwork may allow the fields to green up before the crop can be planted. Occasionally, if the suite of winter annual weed species is adequately controlled, the emergence of summer annual weed species may occur sooner than if winter annuals were still present.

7. Do not utilize a fall herbicide application as an avenue to provide residual control of summer annual weed species. Control of summer annual species, such as waterhemp, is often improved when applications of soil-residual herbicides are made closer to planting compared with several weeks (or months) prior to planting. If a soil-residual herbicide will be part of a fall herbicide application, select an application rate that will provide control of winter annuals throughout the remainder of 2011, and do not increase the application rate in hopes of obtaining control of summer annual species next spring.

8. With the increasing prevalence of horseweed, including glyphosate-resistant populations, fall herbicide applications may prove more efficacious than spring applications. Glyphosate alone may not provide adequate control when applied in either fall or spring, but a fall application timing provides an opportunity to utilize higher application rates of products (such as 2,4-D) than are feasible to use in spring.

Apart from winter annual weed species, fall months may offer a good opportunity to apply herbicides for improved control of certain biennial and perennial weed species. These species often become established in reduced or no-tillage fields and can be difficult to control with herbicides once the populations are established.

For more information on controlling weeds after fall harvest, read The Bulletin online at bulletin.ipm.illinois.edu/.

(Source: Aaron Hager, Extension Specialist, Weed Science/IPM, hager@illinois.edu)

Leave a Reply

Herbicides Stories

Crop InputsMonsanto, FMC Expand Roundup Ready PLUS Platform
August 31, 2015
FMC Corp. and Monsanto Co. announced today an expanded agreement to continue their participation in the Roundup Ready PLUS Crop Read More
HerbicidesREUTERS: Anti-GMO ‘Scientist’ Calls For New Review Of Glyphosate
August 20, 2015
EDITORS NOTE: We feel that it is important to note that there are those that believe one of the lead Read More
Mature Waterhemp in Corn
HerbicidesAustralia’s Seed Destructor Could Be Midwest’s New Tool Against Weed Resistance
August 17, 2015
It’s a piece of equipment that probably isn’t on many Midwest farmers’ radars at this time, but could eventually be Read More
HerbicidesExpert: IARC Herbicide Classifications Leading To Confusion, Misinformation
July 24, 2015
Few people in the crop protection industry had heard of the International Agency for Research on Cancer (IARC) before this Read More
Top 100 Articles
Crop InputsLand ‘O Lakes, United Suppliers Finalize Merger
August 24, 2015
According to a press release on August 24, owners of United Suppliers, Inc. and members of Land O’Lakes, Inc. “have Read More
West Central Cooperative, Jefferson, IA
CropLife 100Iowa Cooperatives To Explore Unification
August 19, 2015
The boards of directors at two of Iowa’s leading farmer-owned cooperatives yesterday signed a letter of intent to study the Read More
CropLife 100Southern States Coop Hosting Drone Flight This Friday
August 3, 2015
Southern States Cooperative — No. 9 on the CropLife 100 — is hosting an FAA-approved drone demonstration at Grandview Farms Read More
CropLife 100Aligned Ag Distributors Adds Four New Owners
July 30, 2015
Aligned Ag Distributors LLC has announced the addition of four new customer/owners to Franklin Holding Co. LLC. They are: The Read More
CropLife 100Pinnacle Purchases California-Based Specialty Crops Retailer
July 20, 2015
Pinnacle Agriculture Holdings has successfully acquired California-based NH3 Service Co.  Operating as part of Pinnacle’s Performance Agriculture brand, the new locations Read More
Asmus Farm Supply liquid fertilizer facility features 20,000 square feet
CropLife 100Slideshow: Asmus Farm Supply Shows Off Its New Liquid Fertilizer Facility
July 15, 2015
Asmus Farm Supply, Rake, IA, recently added a new liquid fertilizer facility to its company operations. The new liquid fertilizer Read More
Latest News
Young soybean field
Industry NewsArysta LifeScience Announces New Business Unit Head For…
September 1, 2015
Arysta LifeScience North America announces the addition of Rico Christensen, Business Unit Head, North America. Christensen will have responsibility for Read More
Wilbur Ellis Pink Soybean Seed Treatment
Crop InputsWilbur-Ellis Goes Pink With Soybean Seed Treatments For…
September 1, 2015
This past year, proceeds of pink-dyed soybeans treated and sold to Wilbur-Ellis seed customers in Chester, SD, went to two Read More
SprayersNORAC Active Wing Roll Slated For More Sprayers
September 1, 2015
NORAC Systems, a member of the Topcon Positioning Group, announces the release of Active Wing Roll for RoGator, Apache, New Read More
Syngenta Sign
FungicidesSyngenta’s Newest Fungicide Receives EPA Approval
September 1, 2015
Syngenta announced today that its newest succinate dehydrogenase inhibitor (SDHI) fungicide – Solatenol – has received registration from EPA and Read More
Flooded corn in Indiana
Crop InputsDelaying The Fertilizer Decision
September 1, 2015
Comments gathered from several retailers recently evidenced a classic good-news-bad-news scenario. Good news is prices and supplies of nitrogen, phosphate, Read More
StewardshipBee Buffer Strip Initiative Seeks 100 Ohio Farmers
August 31, 2015
The U.S. Bee Buffer Project, an initiative of the Pollinator Partnership (P2), Burt’s Bees and The Burt’s Bees Greater Good Read More
2015 ShowStopper Award, MAGIE
EquipmentA ShowStopper From Case IH: The Patriot 2250
August 31, 2015
For nine years now, visitors to the yearly Midwest AG Industries Exposition (MAGIE) show have been tasked with not only Read More
Crop InputsMonsanto, FMC Expand Roundup Ready PLUS Platform
August 31, 2015
FMC Corp. and Monsanto Co. announced today an expanded agreement to continue their participation in the Roundup Ready PLUS Crop Read More
Deere Nutrient Applicator
Eric SfiligojThe Good & Bad News From MAGIE
August 31, 2015
As I write this column, I’ve just returned from the annual Midwest AG Industries (MAGIE) trade show in Bloomington, IL. Read More
CPS Morenci receiving its 4R certification
StewardshipCPS Morenci Becomes First Michigan Facility Certified I…
August 31, 2015
The 4R Nutrient Stewardship Certification Program has announced that Crop Production Services, Inc.’s facility located in Morenci, MI, has been Read More
EquipmentDeere Announces Soucy Track Distribution Alliance
August 28, 2015
John Deere announces an alliance with Soucy Track to sell and distribute products through the John Deere dealer channel. “This Read More
FertilizerFall-Applied Phosphorus: A Rooted Investment
August 28, 2015
As commodity prices decrease and input prices continue to rise, farmers are seeking more efficient strategies for meeting a high Read More
Monsanto Sign
Crop InputsWhat’s Next For Monsanto, Syngenta?
August 28, 2015
After dropping its $47 billion bid to take over Swiss agribusiness firm Syngenta, Monsanto may be turning its focus to Read More
Golden Harvest Corn stalks
Crop InputsMonsanto: Syngenta Not The Only Horse In Crop Protectio…
August 28, 2015
Monsanto Co, having ditched an audacious $46 billion (£30 billion) offer for Syngenta AG, may downshift to a humbler strategy Read More
ManagementConsolidation hits and a miss; And a look at China’s ch…
August 28, 2015
As Monsanto suspends its pursuit of Syngenta, consolidation news at the retail and distribution level heats up. CropLife magazine’s Executive Read More
Corn Field
MicronutrientsHuma Gro Introduces New Boron Liquid Nutrient Formulati…
August 28, 2015
BORO-MAX, a new boron (B) 10% liquid nutrient formulation, has been added to the Huma Gro product line. This new Read More
Crop InputsNFU: Monsanto Decision To Withdraw Syngenta Bid ‘…
August 26, 2015
National Farmers Union (NFU) President Roger Johnson said the organization was very pleased by the news that Monsanto has withdrawn Read More
Crop InputsMonsanto Withdraws Bid For Syngenta
August 26, 2015
Monsanto Co. abandoned its latest effort to acquire Syngenta AG, the world’s top maker of pesticides, after a sweetened bid Read More