3/24/2022

Applying Corn Herbicides in Difficult Weather Conditions

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Sprayer in field prep for planting

In a perfect world, corn farmers would only get the exact amount of precipitation necessary to be able to get fieldwork done and maximize yield. Unfortunately, that’s not the way Mother Nature works. Depending on where you live, you could be seeing extremely dry or extremely wet weather in the forecast.  

What challenges can these different conditions create for your corn herbicide applications and how can you overcome those challenges no matter what weather comes your way this spring? Corteva Agriscience field scientist Kelly Backscheider has some friendly reminders.

Applying Herbicides in Drought

When it comes to excessive rain or drought, Backscheider says, both can be tough, but one is tougher than the other.

“From a herbicide standpoint, if I had to choose, I would honestly rather have it be too wet than too dry,” Backscheider explains. “Typically, in the spring, we don’t see a lot of drought conditions in the Midwest, but we do sometimes. As we know, a lot of the Upper Midwest experienced extremely dry weather through the spring and summer last year.”

Backscheider says drought and dry conditions bring greater challenges to controlling weeds than wet weather. For example, some weeds can grow thick, protective layers to conserve water when it’s dry, which makes it harder for herbicides to get into the weeds and kill them.

“The good thing about dry weather is that we can get out into the field whenever we want to do work, but we also need to remember how those conditions impact our herbicides,” Backscheider explains. “Our herbicides may not work as well if it’s too dry. So, we may want to change up our adjuvants that we’re using and think about the nozzles we’re using to get the right coverage. It’s going to take some more effort to get those herbicides to work when conditions are dry.”

The dry conditions can put a damper on your residual herbicides as well. Most need about 0.5 to 1 inch of rain to activate.

“The good thing about dry weather is that we can get out into the field whenever we want to do work, but we also need to remember how those conditions impact our herbicides.”

“If it’s too dry and you put a residual herbicide out, it might not get activated. It will sit on the soil surface until it breaks down,” Backscheider says. “But if you don’t get adequate soil moisture for several weeks that residual may not get activated and you may have weeds emerging again. That’s something to keep in mind.”

So, Backscheider advises planning ahead and scheduling your applications around the forecast as much as possible. If you see rain in the forecast during a dry time, try to capitalize on it and get your residuals down shortly before then.

“We can’t control the weather and we can’t control when it’s too dry, but if you have a plan in place and a backup plan in place, you’ll be able to adjust when less ideal conditions come about,” Backscheider says.

Applying Herbicides in Wet Conditions

And when you’re facing overly wet weather, Backscheider says, planning is still key, especially for getting the most out of your residual herbicides.

“Having a good amount of soil moisture will activate those residual herbicides. Obviously, you don’t want several inches, but looking at the forecast and planning applications around when you’re most likely to get the right amount of rain to activate those residuals is a good idea,” Backscheider explains. “No matter what, I recommend planning ahead and making backup plans. You may have a perfect program in mind, but if it’s too wet and you can’t get into the field in time, it won’t do you any good. So, having alternative products is important.”

“Having a good amount of soil moisture will activate those residual herbicides. Obviously, you don’t want several inches, but looking at the forecast and planning applications around when you’re most likely to get the right amount of rain to activate those residuals is a good idea.”

Backscheider says no matter what you’re seeing in the forecast, having flexible herbicides with wide application windows in your weed control program is a great step toward overcoming Mother Nature’s challenges.

“Overall, it’s important to have products that offer great flexibility. That’s why I like a corn solution such as Resicore herbicide. It can be applied anywhere from preplant to preemergence to postemergence on corn up to 11 inches tall. So if you can’t get into the field to make applications when you originally intended to, having a product like that in your program gives you that flexibility to get in there when you can and keep your fields clean,” Backscheider explains.

We hope Mother Nature treats you well in 2022, but if she puts hurdles in your way, Backscheider advises working closely with your local retailer to find the right solutions to keep your cornfields clean. You also can visit the corn herbicides portfolio website on Corteva.us to see which products fit the way you farm.

Resicore® is not registered for sale or use in all states. Resicore is not available for sale, distribution or use in Nassau and Suffolk counties in the state of New York. Contact your state pesticide regulatory agency to determine if a product is registered for sale or use in your state. Always read and follow label directions.