There isn’t a better control option than glyphosate, at really, any cereal rye stage (size). Some research suggests 0.75 lb of acid equivalent/ac is enough to control even large cereal rye, other recommendations suggest it took as much as 1.5 lb of acid equivalent/ac of glyphosate to terminate cereal rye.
Why this difference?
The weather and the air temperature play a big part in killing cereal rye. If we don’t have good growing weather for plants to grow, we won’t get an effective kill. Plants need to be growing in order to take up the chemistry and start working. To get a good effective kill, glyphosate needs 3 days of air temperatures in the mid 50’s for highs and not below 40 degrees F for evening lows. These temperatures are required for active growth, which enables the glyphosate to get absorbed and for good movement throughout the plant for an effective kill. So be looking for that 3 day window come early this spring. I recommend the higher 1.5 lb a.e. rate if you even suspect temperatures won't be ideal during application. Not killing cereal rye can have significant impacts on cash crop yields so increasing the rate of glyphosate is a relatively cheap alternative to manage risk. As they say in the industry, a dead weed is a good weed!
If you’re looking for options to enhance broadleaf control in your burndown program, adding Sharpen® (saflufenacil), 2,4-D, or Dicamba will not antagonize the glyphosate, but HPPD inhibitors, atrazine, and metribuzin will.
Don’t forget appropriate adjuvants
For glyphosate, NIS is optional, depending on situational instances. Given the possibility of challenging weather during early spring, we recommend NIS at 0.25% V/V. Finally, the AMS must be included. The AMS will:
- reduce any antagonizing effects of hard water
- increase effectiveness in challenging environmental conditions
- reduce the antagonistic effects from any other thank mix partners
You should be able to reach all of these goals by using a minimum of 10 lbs of AMS per 100 gallons. It’s always important to completely dissolve the AMS prior to adding glyphosate. Liqui-Grow’s Agronomy Field Advisors have experience in terminating cover crops, so be sure to reach out with any questions!
The Extras:
It’s worth noting that if you apply glyphosate with Sharpen® (saflufenacil), 2,4-D, or Dicamba, any required adjuvants on those herbicide labels must be added to this glyphosate tank mix. Finally, do not use ATS or UAN as a carrier when terminating cereal rye; those fertilizers will injure the cover crop enough that the uptake of the glyphosate may be reduced, resulting in less kill.