Time to Check the Calendar

Starting with a good foundational PRE herbicide gives us the most flexibility and widest window for a successful POST application. After we've started with a good foundational PRE herbicide, like Zidua^® PRO Herbicide for soybeans or Verdict^® Herbicide for corn, when do we make the POST application?

📸: BASF employee/Featuring a field example for a good foundational PRE herbicide.

Glyphosate resistance has changed the timing for POST herbicide applications.

📸: BASF employee/Featuring rows of emerged crops.

Glyphosate Resistance: The Shift Towards Strategic POST Herbicide Timing

Glyphosate spoiled us, and most of us went away from calendar sprays because we could knock down large weeds effectively whenever we got around to it. Now that glyphosate resistance is widespread, we need to be more strategic in the timing of POST herbicide applications.  

Calendar Sprays vs. Reality: Why One Size Doesn't Fit All for POST Timing 

The calendar spray method may be the easiest way to get POST applications done. In this method, a grower marks on the calendar a date after a PRE application. For example, at 6 oz per acre, we expect Zidua^® PRO Herbicide to give at least a month of residual weed control, so we mark our calendars at 5 weeks after application.

📸: BASF employee/Featuring a field example with good timing for a POST herbicide application.

Beyond the Label: Field Variables Affecting POST Herbicide Performance

In addition to the product you choose and the rate, field variables like dominant weed species, weed population (weed seed bank), soil type, soil microbe populations, rainfall, temperature, and other environmental variables can have a profound impact on the length of weed killing power of a residual herbicide in the soil.  

Early Intervention is Key: Targeting Weeds Before They Become Unmanageable

It's better to spray the POST a little early than go up against weeds that are too big for a successful POST application.  

The Power of Two: Combining POST Herbicides with Residuals for Extended Weed Control

We want to add residuals (e.g., Outlook^® Herbicide or Zidua^® SC Herbicide) to our POST applications so we don't leave a gap in weed control. If we do it right, we have a successful two pass program that doesn't waste time and money on a challenging 3rd application.

Before mixing components, always conduct a compatibility jar test. Always consult respective product labels for specific mixing instructions. The most restrictive label applies.

Always read and follow label directions. Grow Smart, Zidua, Verdict, and Outlook are registered trademarks of BASF. All other trademarks are the property of their respective owners and use of any such trademark does not imply any affiliation with or endorsement by its owner. © 2024 BASF Corporation. All rights reserved.