A large general rain yesterday and back to winter temperatures this morning keeps field progress in slow motion again this spring. As soon as the weather permits corn planting will take priority followed by late burndown in some fields.
What should my burndown strategy be with planting time upon us? In some cases it will be too close to planting to apply dicamba which has been our “go to” glyphosate-resistant horseweed herbicide. Sharpen would be a good new “go to” in these situations for soybean burndown.
In cotton, please refer to the label of your dicamba product as there are differences in plant back. The most notable is that Clarity has a supplemental label that allows cotton to be planted 14 days and 1” of rainfall after Clarity is applied. All the other generic formulations of dicamba (Banvel, Rifle, Agri Star, etc) have a 21 day and a 1” of rain waiting period before cotton can be planted. Horseweed is now growing rapidly and some I have looked at are 3 to 4” tall. Below are some more thoughts on late horseweed burndown in cotton and soybean:
Late Season Burndown Options for Cotton
Dicamba 8 ozs/A + Roundup PM 32 ozs/A
Management Considerations
- Clarity rates of 8 ozs/A can be applied up to 14 days before planting and 1” of rainfall to avoid crop injury.
- Generic dicamba products at rates of 8 ozs/A can be applied up to 21 days before planting and 1” of rainfall to avoid crop injury.
- Remember to use a surfactant (0.25% NIS) with dicamba applied alone or with a glyphosate product that has no or moderate surfactant load.
Gramoxone Inteon 40 to 48 ozs/A + 0.25% NIS + Caparol 32 ozs/A or Cotoran 32 ozs/A.
Management Considerations
- This application can be applied right up to planting.
- Gramoxone Inteon rates below 40 ozs/A will not provide as consistent control of horseweed as higher rates.
- For larger horseweed (>6”) use 48 ozs/A of Gramoxone Inteon.
Late Season Burndown Options for Soybean
Sharpen 1 oz/A Or Verdict 5 oz/A + Roundup PM 32 ozs/A
Management Considerations
- Sharpen at rate of 1 oz/A can be applied right up to planting.
- For large horseweed (>4”) consider increasing Sharpen Rate to 1.5 oz/A or Verdict to 7.5 ozs/A and/or 1 pt of 2,4-D. – Plant back to soybean for higher rates of Sharpen or Verdict is 14 days; Plant Back for soybean is 7 days after a Pint of 2,4-D.
Dicamba 8 ozs/A + Roundup PM 32 ozs/A
Management Considerations
- Dicamba rates of 8 ozs/A can be applied up to 14 days before planting and 1” of rainfall to avoid crop injury.
Gramoxone Inteon 40 to 48 ozs/A + 0.25% NIS + Sencor 4 ozs/A or Canopy
4 to 6 ozs/A or Boundary 20 ozs/A.
Management Considerations
- This application can be applied right up to planting.
- Gramoxone Inteon rates below 40 ozs/A will not provide as consistent control of horseweed as higher rates.
- For larger horseweed (>6”) use 48 ozs/A of Gramoxone Inteon.
FirstRate 0.3 to 0.4oz/A + Roundup PM 32oz/A
Management Considerations
- This application can be applied right up through soybean emergence.
- FirstRate will not provide good control of horseweed under cool conditions.
- FirstRate performance is temperature dependent. Works best with highs in the 80s and lows in the 60s.
