Wallaces Farmer

Does a dry season mean fewer weeds? Hold that thought.

Experts weigh in on how a dry 2023 could mean more weeds going into next season. Find out what you can do now to get ahead for next year’s crop.

September 15, 2023

3 Min Read
Does a dry season mean fewer weeds?
Submitted by Brevant seeds

Weeds don’t take the year off — even in a dry season.

The 2023 season was a dry year across the Midwest, with slow-growing crops pushing through thanks to a few well-timed showers and late-season moisture. Some fields didn’t come out as fortunate.

Either way, experts say the drier-than-average season could create a “perfect storm” for higher weed pressure next spring.

Matt Karls, retail product agronomist for Brevant® seeds, said his area in Wisconsin was very dry in spring and early summer, when many acres went a month without rain. Some farms didn’t see moisture for nearly two months. That meant a rough start for weed control in many corn and soybean fields.

“Many farmers didn’t have the rainfall to activate residual herbicides at planting,” Karls said. “And in many cases, drier conditions at planting continued into the first and second pass of herbicides.”

In addition to limited herbicide activation, the dry weather meant corn and soybeans didn’t close the canopy — allowing weeds ample sunlight to germinate longer. In many cases, that led to higher weed populations that were ready to grow when they did catch a rain.

On top of that, some weeds are more difficult to control in a drought. In his area, lambsquarters is a problem every season, but it’s amplified in drought years.

“We have heavy populations of lambsquarters, and they have a real advantage in dry weather,” Karls said. “During a drought, lambsquarters can develop a thick waxy layer on the leaf surface that inhibits herbicide uptake. That makes them even more difficult to control in a dry season.”

Challenges can continue later in the season. If corn missed pollination due to heat, farmers may cut the corn for silage. Also, stalk quality may be reduced during a drought year, and the corn crop may need to be harvested earlier due to stalk degradation. Joe Bolte, Corteva Agriscience market development specialist, said either situation opens the door for increased weed pressure.

“When you cut corn for silage, you have less crop residue in the field and the weeds have an opportunity to germinate a little sooner because they don’t have competition,” Bolte said. “The same is true for earlier harvested corn. If you have an empty field sooner and then get the right temperature and moisture, it could promote winter annual germination.”

Bolte covers parts of Missouri and eastern Kansas, and he’s seen marestail germinate in September under the right conditions. When winter annuals come early, they create a secondary problem: good overwintering habitat for corn and soybean pests.

“You really want to control weeds in the fall, because soybean cyst nematodes overwinter in weeds such as henbit and cutworms lay their eggs in weedy spots during the spring,” Bolte said. “Fall weeds may not seem like such a problem now, but they can cause big issues next season.”

Bolte said farmers should talk with their retailers to get local recommendations for fall weed control products. Options will depend on prevalent weed species and the planned crop for next year.

“Afforia herbicide is a great choice that allows you to plant corn or soybeans next season. Basis Blend can be a great option when planting corn the following year,” Bolte said. “If you know you’re planting soybeans next season, consider Trivence herbicide or Envive herbicide. Finally, Elevore herbicide is a really good fall burndown that offers excellent control of difficult marestail.”

For more advice on fall burndown options or choosing Brevant® brand products for 2024, connect with your local ag retailer. Find yours at Brevant.com/Retail.

™ ® Trademarks of Corteva Agriscience and its affiliated companies. Afforia®, Basis® Blend, Elevore®, Envive® and Trivence® are not registered for sale or use in all states. Contact your state pesticide regulatory agency to determine if a product is registered for sale or use in your state. Consult product labels for geographical restrictions, rates and all other restrictions. Also, consult labels on maximum active ingredient per season when planning your herbicide program. Always read and follow label directions. © 2023 Corteva.

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