Growing Knowledge

Read the latest insights from our experts as they cover agronomy issues that matter most to you and your operation.

Does Fall Burndown Pay Off?

George Watters
Agronomy Manager
For farmers who adopt minimum- or no-till practices, controlling weeds throughout the fall can be crucial — particularly for winter annual weeds like marestail and perennials such as dandelions. Overwintered marestail, for example, is very difficult to control in the spring.
 
If we are able to harvest early and we have warm, dry weather, we’ll have a wider window of opportunity for fall herbicide applications.
 
Benefits of Fall Weed-control Applications
There are a number of advantages to doing a fall burndown:
  • Smaller weeds: Weeds are typically smaller in the fall, making them easier to control.
  • Weeds are getting ready for winter: During the fall, plants are translocating most of their nutrients to the roots for overwintering. This means more of the herbicide will move down into the roots and provide good control.
  • Less compaction: Drier soils are better suited to sprayer traffic, minimizing compaction.
  • Earlier planting: With more effective control, fields can dry and warm faster in the spring to allow for tillage and earlier planting.
  • Greater efficiency: Equipment works better in clean fields.
  • Less weed competition: Early-season weed competition is reduced to help crops get a good start and encourage uniform stands.
  • Fewer pest havens: Fewer weeds mean fewer egg-laying sites for insects such as spider mites and cutworms, and no alternate host for soybean cyst nematodes.
Spring Application? Possibly.
Don’t forget to manage weeds into next spring as well. In spite of its benefits, fall burndown generally doesn’t eliminate the need for a residual herbicide program in the spring to achieve effective, season-long weed control.
 
For specific weeds like marestail (a big problem in the eastern Corn Belt), you may also need a spring burndown to take care of what germinates in the season’s early weeks. But if you do a fall burndown, you can at least avoid dealing with tough-to-control, overwintered marestail.
 
Contact your local WinField United retailer to learn more about fall burndown options in your area.

Forge Ahead on Late-Planted Corn

Glenn Longabaugh
WinField Agronomist
Has a wet spring put a damper on your corn crop or even made you think about replanting your corn fields? Many farmers are pretty far along with corn planting, but lately some have experienced heavy, flooding rains and are assessing whether or not they’ll have to replant.

It looks like it was cold enough in my area of southern Indiana during our flooding period that some of the corn was not actively respiring, and now appears to be recovering well. There is still the danger of seedling blight, the resulting crown rot as well as downy mildew (crazy top), but the corn crop is looking better every day. Input prices are also falling. Nitrogen, for example, is less expensive than it has been, which makes corn more attractive.

Here are some tips for helping make delayed planting successful.

Don’t replant with significantly earlier-maturing corn.
We do not encourage farmers to plant extremely early hybrids as we get into late planting. Many times, earlier hybrids are not well-suited for heat, and late-planted corn often flowers in some of the harshest conditions of the year. An early hybrid is often a poor option.

Maintain populations.
Some schools of thought believe farmers need to plant at higher populations. But most of the time, planting later with the same population as you would have earlier results in better stands, because of more favorable conditions after planting. With corn, farmers get better emergence or more even emergence when they stick with a reasonable planting rate. So if you plant your corn at, say, 32,000 seeds per acre early, I’d recommend maintaining that population if you need to replant later.

Get a handle on weed control.
Weed control probably gets easier as we get into late planting, as long as you start clean. If you are a conventional tillage farmer and are starting with clean fields, you’re more likely to experience success with a one-pass program in corn. If you’re a no-till farmer, it is absolutely imperative that you confirm your burndown has terminated all weeds. If you don’t start clean, you can never stay clean. Later in the season, those weeds that emerged early are going to be more robust, taller and harder to manage.
 
If you made an early burndown pass, had to delay planting and now have regrowth, you’ll need to do a second burndown application along with your first residual when your fields dry out. 

Locking in Spray Investments

Joel and Kyle
Hosts, WinField
Host Joel Wipperfurth and agronomist Mark Glady talk about ensuring the effectiveness of spray applications on this episode of The Deal With Yield®. Hear their tips for which products to add to the spray tank and how to stay ahead of herbicide resistance.
Season 9: Episode 3 – Locking in Spray Investments

The Deal With Yield is a podcast series covering the issues that matter most in crop production.

Managing the RoundUp Ready® Xtend Crop System: Part 1

Joel and Kyle
Hosts, WinField
On this season opener of The Deal With Yield®, host Joel Wipperfurth and guest Ray Pigati, WinField United Crop Protection Technical Marketing Specialist, kick off their in-depth discussion of the RoundUp Ready® Xtend Crop System. Get a look into the rapidly changing approval process of this new technology, like the need for each state to approve the label. Learn how to manage multiple sites of action to prevent herbicide resistance and how variety selection can lead to the specific herbicide you should use.
Season 8: Episode 1 – Managing the RoundUp Ready® Xtend Crop System: Part 1

The Deal With Yield is a podcast series covering the issues that matter most in crop production.

Preparing for 2017 Weed Challenges in Soybeans

WinField United
Agronomy Team
If 2016 was any indication, soybean farmers should be ready to combat tough weed competition in the coming season. Herbicide-resistant marestail, waterhemp, Palmer amaranth, kochia and some ragweed species were leading problems during 2016 in Midwest soybean fields (see state recaps below). 
 
With resistant weeds on the rise, a complete herbicide-resistance management program is needed to take control, starting with a clean field at planting. Other recommended steps include crop rotation, three effective modes of action, overlapping residuals, timely applications use of full-label rates for herbicides with complementary adjuvants. With similar weed issues reported in both corn and soybean fields, a holistic approach across all crops in a rotation is needed.
 
While farmers may consider planting the recently approved dicamba-tolerant soybean system, the new dicamba formulation only counts as one of the three modes of action needed. Another option is to plant LiberyLink® soybeans and then use Liberty® herbicide as an in-crop application. 
 
WinField United agronomists recently shared some soybean weed insights from 2016 in this Corn & Soybean Digest article. Highlights by state are below.
 
Illinois: Glenn Longabaugh says the biggest 2016 weed-control issues in Illinois soybean fields were tall waterhemp and Palmer amaranth. Because of resistance to multiple herbicide groups across Illinois, including Groups 2, 5, 14 and Group 9 (glyphosate), a comprehensive herbicide-resistance management strategy is needed for acceptable control in any system, including non-GMO soybeans, Longabaugh says.
 
Indiana: Pigweed species, in particular tall waterhemp and some Palmer amaranth, provided the greatest challenge for Indiana soybean farmers in 2016, says George Watters. Nearly 100 percent of the waterhemp and Palmer amaranth populations are now resistant to glyphosate (Group 9) and ALS (Group 2) herbicides. Several populations are also becoming resistant to foliar applications of PPO (Group 14) herbicides. To best combat these challenging weeds, Watters recommends that farmers use a comprehensive herbicide-resistance management program.
 
Iowa: Resistance to glyphosate and Group 14 herbicides caused the biggest waterhemp control problems in Iowa soybean fields during 2016, Ryan Wolf notes. The appearance of Palmer amaranth also had Iowa farmers closely monitoring their fields. Higher rates of preemergent herbicides along with metribuzin in preemergent tank mixes provided the best weed control success. Timely post-applications also performed well. 
 
Michigan: Roundup Ready®- and ALS-resistant marestail was the biggest problem in Michigan soybeans, says Allen Pung. In addition to a good preemergence herbicide program, many farmers are also considering either LibertyLink® soybeans or the new dicamba-tolerant soybeans for 2017. A light tillage pass can also be helpful, he advises.
 
Minnesota: Herbicide-resistant weeds, including tall waterhemp, giant ragweed and common ragweed, were the top weed challenges for Minnesota soybean farmers, reports Al Bertelsen. In addition to identifying resistant weeds early and using at least three effective modes of action, Bertelsen recommends timely applications of PPO herbicides when weeds are small for improved weed control in in 2017. Because PPO herbicides require more spray coverage than glyphosate does, he advises spraying at higher volumes and selecting spray nozzles that increase weed coverage.
 
Ohio: Joe Rickard reports that marestail continued to be a major problem for Ohio soybean farmers. Farmers who have been making two applications of glyphosate or using the same chemistry for the past several years may not be receiving the same control as they did five or 10 years ago and should review their treatment options. He recommends a fall treatment to clean up winter annuals, followed by an effective residual herbicide mixed with 2,4-D to control weeds prior to planting. Spring preplant applications are also a good control option.
 
South Dakota: Ryan Wolf reports that weed resistance continued to challenge South Dakota soybean farmers. In 2016, waterhemp resistance to glyphosate and Group 14 herbicides was more prevalent in soybean fields, especially when spraying was delayed due to weather conditions. Glyphosate-resistant kochia and marestail were also problems. Farmers who used higher rates of preemergent herbicides and added metribuzin to their preemergent tank mixes had the most weed control success. Timely post-applications also performed well. 
 
Wisconsin: Tall waterhemp was the biggest weed challenge in Wisconsin soybean fields during 2016, says Todd Cardwell. While this weed isn’t new, glyphosate-resistant varieties have become difficult to control and have spread dramatically. Planning ahead and designing a long-term program is the best way to combat weed problems in 2017 and beyond, he advises. Farmers can address glyphosate and triazine resistance by making sure that their weed control program includes products that are still effective on resistant species. Some of the older chemistries like metribuzin (Dimetric® DF 75% or Sencor®) have been effective on glyphosate-resistant waterhemp. 

For similar insights on corn weed challenges, click here.

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