Evaluating Your 2021 Weed Control | The More You Grow | Corteva Agriscience
 12/14/2021

Evaluating Your 2021 Weed Control

Evaluating weed control

Past experience is one of the very best teachers to prepare for future challenges. Knowing that, it’s important to look back at how your 2021 weed control program fared to help plan to keep your corn and soybean fields clean in 2022. Reviewing your program’s successes and shortcomings can set you up for even better yield potential. 

Weed Control Review List

Joe Armstrong is the zonal biology leader for row-crop herbicides at Corteva Agriscience. He says the first step to take when reviewing your 2021 weed control program is to run through a checklist of items that likely impacted how well it performed. Some of those items include:

  • Weeds you needed to control 
  • Herbicides you used 
  • Cultural practices you used 
  • Weather events 
  • Weed escapes 
  • Timing  

“Basically, you want to evaluate any variable that could have had an effect on weed control. Weather and environment are probably the biggest concerns, but other things like products used, adjuvants, use rates, application timing and the size of the weeds at application are also very important,” Armstrong explains. “Weed escapes and understanding which weeds may have survived the season are also very important to consider.” 

Armstrong says, for example, if you found a large patch of weeds that survived your herbicide application(s), you will want to consider if those weeds are resistant to the solutions you used. One way to know for sure is to send a sample of the weed to a diagnostic lab, if possible. Once you know whether you’re dealing with resistant weeds, you can alter your weed control program accordingly for next year. 

Armstrong says it’s also important to take note of any new weed species you saw in your fields in 2021. He says you’ll want to try to understand where those weeds came from and find out if you need to add any new modes of action or practices into your program to control them in the future. 

Using Your Data

It’s likely you’ve been keeping notes on a lot of the aforementioned information throughout the season. The end of the year is a great time to pull all that data together and even look at weed control data from years past to get a fuller picture of what you’ll need to do in 2022. And if you don’t have that information on hand, now is a good time to start keeping track. 

“I like the saying, ‘you can’t manage what you don’t measure.’ When applied to weed management, if you aren’t measuring the effectiveness of your weed control efforts from year to year and field to field, you won’t be able to make informed decisions on which herbicides, or other weed control methods, worked best for each field,” Armstrong explains. 

Having a solid understanding of the solutions and practices that worked best for weed control and a solid understanding of what did not work so well can help you overcome future challenges. 

“For example, if your preemergence products did not work as well as they typically do, was it because of weather (lack of early-season rainfall or too much rainfall) or timing (applications went out too late)?” asks Armstrong. “If a postemergence application did not work as well as expected, was it because of an incorrect rate (maybe too low for the target weeds), incorrect adjuvant (label called for COC, but you used NIS), or developing resistance?” 

Once you know what the weak link was in your weed control program last season (or in previous seasons), you can strengthen that link in 2022 by making the necessary alterations. 

Armstrong says, regardless of whether you implement changes next year, it is imperative that you continue to keep detailed records of your weed control season over season. This will help strengthen your plans in the short term and help fight herbicide resistance in the long term.  

“This lets you see the various products, active ingredients and modes of action that you have been using, allowing you to evaluate the diversity of your herbicide programs across crops,” he explains. “Good records will also help when planning crop rotations and optimal planting dates for next year to make sure you don’t run into any plant-back concerns due to herbicide carryover.” 

2022 Weed Control Challenges

Every year is unique and brings its own challenges to fields. Armstrong says, as far as 2022 goes, two of the most concerning weeds will continue to be waterhemp and Palmer amaranth. Both weeds have developed resistance to multiple herbicide modes of action in several states. Both weeds are also capable of robbing corn and soybean yield. 

Armstrong says the supply chain will also be top of mind for anyone working in the ag industry going into the new year. He says it may be difficult to get certain postemergence herbicides that are manufactured overseas, but you can create a strong herbicide program regardless. 

“If you know your postemergence herbicide options may be limited, investing in a strong preemergence residual herbicide will help maximize your weed control early in the season and reduce weed pressure later in the year,” Armstrong explains. 

To help find the right preemergence and postemergence solutions for your fields in 2022, you can visit the soybean herbicides portfolio and the corn herbicides portfolio websites from Corteva Agriscience. And remember to keep track of your weed control data next year to help set yourself up for cleaner fields in 2023 and beyond.