The following is from Dr. Eric Prostko on pigweed emergence:
Just a heads up to you and your growers that Palmer amaranth has already emerged in the field (Figure 1). Consequently, strip-tillage peanut growers who are applying burndown herbicides (Roundup, Gramoxone, 2,4-D) now should seriously consider including a residual herbicide with the burndown. I would suggest either Valor SX 51WG @ 2 oz/A or Dual Magnum 7.62EC @ 16 oz/A. Residuals included with the burndown herbicide program should help keep peanut fields pigweed free until planting.