A baseball team can’t win by hits alone. Or by not making errors. Or even with a pitcher who throws a no-hitter. It takes the combination of batting, fielding and pitching to take home the win.
It’s the same when it comes to farming and spraying herbicides. You can’t bank on maximum weed control without all-around excellent stewardship, including:
- Applying the proper spraying techniques for contact and systemic herbicides
- Selecting the right herbicide for your farm a herbicide with the right residual for your weed management program
Whether you’re out in the fields spraying corn or soybeans, we’ll take a closer look at how actively incorporating both management practices on your farm brings home the win to stay one step ahead of resistance. By keeping the following practices in mind, weeds are minimized and yield maximized.
Know Your Herbicides: Contact vs. Systemic
The most important step you can take to spray properly is to know which kind of herbicide you are applying: contact or systemic? According to Purdue University, contact herbicides are classified as controlling only the green portion of the weed that they touch. The chemical activity is so rapid that the herbicide moves very little within the actual plant itself. This makes ensuring herbicidal contact with weeds especially critical. One such corn and soybean contact herbicide is Liberty®, which is applied to LibertyLink® corn and soybeans.
With a unique mode of action, Liberty herbicide allows you to manage weeds before they jeopardize yield potential. To get the most from Liberty herbicide, remember this acronym: S.T.O.P.
Start early with the first application.
- Early action against weeds is key, so start early with the first application soon after emergence. Scouting weeds and taking early action influences your success.
Target less than 3-inch weeds.
- Successful control starts when weeds are small and easiest to manage.
- Liberty is a contact herbicide, requiring thorough spray coverage, so how it is applied is key to Liberty’s effectiveness and your ability to control weeds. Warm temperatures, higher humidity and bright sunlight are ideal application conditions.
- It starts with the right nozzle. Pick one that generates a medium spray droplet.
- Use plenty of water — at least 15 gal/A to ensure full coverage. In arid conditions or where a dense canopy exists, use 20 gal/A.
- Watch ground speed. Keep ground speed to less than 10 mph for full coverage.
Pair with residuals.
- The key to preventing resistance is to reduce the pressure caused by using a single herbicide mode of action. Make sure to use multiple effective modes of action. Use pre-emerge residual herbicides and a residual tank mix partner for best results.
For additional information on spraying guidelines, check out the Liberty Corn Application Guide and Liberty Soybean Application Guide.
The second type of herbicides, systemic or translocated herbicides, moves throughout the weed – such as Palmer amaranth – to take control. The chemical activity starts by either being taken in by the foliage and moving downward to the roots or entering at the root level and working upward through the weed tissues. When it comes to controlling weeds in your cornfields, systemic products such as Corvus® pre-emergence herbicide, Capreno® postemergence herbicide and DiFlexx® pre- to postemergence herbicide destroy root, leaf and shoot growth.
For spraying both contact and systemic herbicides, Ohio State University Professor and Extension Specialist, Erdal Ozkan, Ph.D., emphasizes the following two application practices to keep sprayer accuracy and efficiency in check:
- Nozzle choices: Keep spray drift in mind when spraying chemicals. For example, nozzles producing large size droplets will produce desired accuracy when spraying systemic herbicides, the contact-type herbicides require maximum coverage on the target surface. This may require nozzles that produce small to medium size droplets. Liberty herbicide requires medium-sized droplets. However, conventional nozzles producing such droplets will also produce very fine and fine droplets which lead to spray drift. Low-drift nozzles are the best technology to reduce spray drift while producing adequate spray coverage. Travel speed and boom height adjustments are additional techniques to address drift issues.
- Fine-tuning: Calibration is one important aspect of fine tuning a sprayer. This includes checking nozzles for wear to make sure the flow rate is acceptable, and determining the actual application rate of the sprayer in gal/acre. Even ensuring tires are properly inflated is important for accuracy of the sprayer. Make sure there are no leakage in the system all the components of the sprayer are functioning as expected.
Selecting the Right Residual: Persistent vs. Non-Persistent
As with the classification of herbicides, there are also two types of residual when it comes to weed control: persistent versus non-persistent. Purdue University defines persistence as, “an important characteristic when long-term residual weed control is desired for total vegetation control.” While persistent herbicides remain active for an extended period of time, non-persistent herbicides do not.
For prime persistence, Capreno has the longest-lasting residual of any postemergence corn herbicide. The optimum residual delivers season-long control of the toughest weeds to deliver an amazing end-of-season clean and controls more than 65 grass and broadleaf weeds, including those resistant to glyphosate, PPO, ALS, dicamba and triazine chemistries.
A pre-emergence persistent herbicide option offered to corn growers is Corvus. Corvus not only contains a powerful residual, but it also has a reactivation feature that rejuvenates the residual with a half-inch of rain. This extends pre-plant control to prevent late-emerging weeds.
Although selecting a top-notch corn herbicide is key when it comes to weed control, it is up to you to apply the labelled use rate. This ensures maximum performance of the product.
Corn grower Lowell Seagren believes in using labelled application rates on his farm. “We have pretty good weed control because we apply Corvus using the full application rate. We do that because I think it’s important to have clean fields and give the corn plants a good chance to yield at their full potential.”
Gordon Seggebruch is another grower who stands by applying Corvus herbicide at the recommended rate. “Corvus is my first choice when it comes to weed control in my cornfields,” he says. “I’d recommend it to other growers 100 percent. But I’d tell them to use the full rate, don’t skimp. Then you will always have clean fields.”