Fall Herbicide Tips for Strong Weed Control

Best fall practices for corn soybean and wheat fields

As reported on the OMAFRA website fieldcropnews.com, Ontario crop specialists are reminding Ontario farmers of the importance of fall herbicide applications to control perennial weeds in corn, soybean, and wheat fields.  

Timely treatments in the autumn can reduce weed populations by over 20 percent and delay shoot emergence next spring, giving crops a strong competitive advantage. 

Field Conditions and Growth 

Corn, soybean, and winter wheat fields across Ontario are progressing well, but variable fall weather means herbicide performance can differ. Warm daytime temperatures and soil moisture remain important for proper herbicide uptake. Farmers are watching for dry spots in some regions while other areas have experienced light frost. 

Key Tips for Fall Applications 

Experts recommend choosing effective herbicide products, using the right rates, and selecting proper tank-mixes for each perennial weed species.  

Products containing glyphosate remain a key tool, with label rates ranging from 1.0 to 3.2 L per acre depending on the weed. Tank-mix partners such as 2,4-D, Distinct, Express SG, or Lontrel XC can improve control of resistant species like Canada fleabane and tufted vetch. 

Spraying should be done when air temperatures stay above 8°C for at least two hours. Late morning to mid-day is ideal for best absorption. After a frost, wait two to three days to ensure plants are healthy before resuming applications. 

Farmers are advised to delay tillage for at least 72 hours after spraying—longer if product labels suggest—to allow the herbicide to move through the entire plant. 

By following these steps, Ontario corn, soybean, and wheat growers can limit weed competition and protect yields for next spring. 

For more information about the Canada fleabane, please visit the Farms.com Field Guide Pest pages. 

Read the related article: Ontario’s most problematic weed -- Canada Fleabane Cuts Corn and Soybean Yields 

Photo Credit: gettyimages-dszc