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Corn Weeds

All Corn Weeds Content

aerial view of South Dakota farm and surrounding land


During the growing season, SDSU Extension provides weekly production recommendations.

Marestail growing abundantly in a soybean field.

Marestail Fall Control

Marestail (also known as horseweed) is considered either a winter annual or biennial species that is often difficult to identify at the rosette stage. In the Dakota’s, marestail will germinate in the fall and bolt in the spring.

Tall, slender kochia weed growing in a test plot.

The Fall Advantage of Kochia Control

Kochia is a problem in north central South Dakota row crops. New post-emergent options in corn and soybean have helped alleviate kochia competition from many fields, but these herbicide options shouldn’t be completely relied upon for a long-term control plan.

corn field with sunrise in the background


Nearly one out of every three dollars generated by South Dakota agriculture starts in a corn field. Two of every three rows of corn become ethanol.

Paul O. Johnson making notes about a field of corn

SDSU Extension to Tackle Weed, Pest and Drought Inquiries at State Fair

August 23, 2021

To address drought concerns, as well as weed and pest inquiries, South Dakota State University Extension will feature two booth locations at the 2021 South Dakota State Fair Sept. 2-6 in Huron.

plant with herbicide damaged leaves

Herbicide Damage to Fruits and Vegetables

Each year in early summer, many growers begin to notice distorted leaves on their fruits, vegetables, and crops. Most commonly the cause is a herbicide application to a nearby field.

Young corn seedlings emerging from a spring field.

Watch Closely for Weed Emergence

Cool, dry conditions have slowed weed emergence and growth, but dry conditions also have limited the activation of preemergent chemicals. Given this scenario, fields need to be scouted closely to ensure that weeds do not get away.

A farmer watching the sun rise in a bare, unplanted field.

Crop Tolerance to Soil Herbicide Residual

Some herbicides can persist in soil, especially dry soil. Herbicide carryover could be an issue in 2021 across the state depending upon last year’s moisture levels and field conditions.

Several ears of sweet corn on a table.

Weed Control in Sweet Corn

When growing sweet corn on a large scale, weed control can be challenging, and certain steps need to be taken before choosing an herbicide.

Field pea cover crop blend growing in a field of corn residue.

Herbicide Residual Effects on Cover Crops After Corn Silage

As cover crop usage has increased in recent years, managing weeds through a longer residual herbicide program has become more complicated. Learn some considerations for cover crops following corn silage.