Source: Penn State Extension
Oct. 1, 2013 — We have discussed this in the past, but it probably requires a review again with no-till wheat and other seedings commencing:
For no-till establishment of winter cereals, glyphosate or Gramoxone can be used to control emerged vegetation prior to small grain emergence.
The Banvel, Clarity and other dicamba labels state that application may be made before, during, or after planting of small grains. Banvel may be applied at 2 fl. oz. /A or Clarity at up to 4 fl. oz. /A with any glyphosate formulation labeled for use as a pre-plant application to small grains with no waiting period prior to planting. East of the Mississippi River, for barley, oat, wheat, and other grass seedings, the interval between application and planting is 15 days per 8 fl. oz./A applied.
The 2,4-D use guidelines are less clear. None of the 2,4-D labels specify application just prior to wheat or other small grain planting/emergence. The most relevant guidelines on most 2,4-D product labels pertain to use on “fallow ground” or between crops. These guidelines state that only labeled crops may be planted within 29 days after application and that risk of crop injury or loss is greatest during the first 14 days. The more soluble amine formulation certainly increases the risk for injury. Although there is some risk of stand reduction and injury to small grains from 2,4-D, application a minimum of 7 days ahead of planting at a pint/A or less should reduce this potential. The use of 2,4-D burn-down in wheat is ambiguous at best. If injury occurs, liability rests with the consultant or applicator.
Sharpen may be applied pre-plant or pre-emergence at 1 to 2 fl oz/A to wheat, barley, rye, and triticale to help with burn-down and/or provide limited residual control of certain broadleaf weeds. The 2 oz. rate will provide limited residual control of broadleaf weeds. To broaden the spectrum, Sharpen can be tank-mixed with Clarity (dicamba) or glyphosate. Do not apply Sharpen to emerged crops.