Application of burndown plus residual herbicides in early spring (late March/early April). This accomplishes the goal of applying early enough to ensure that burndown of emerged plants is not an issue. We have had consistent results with 2,4-D applied this early for marestail control. Applying all of the residual herbicide at this time can result in late-emerging marestail escapes in late May or early June if the residual herbicide activity runs out by then.

Keys to making this approach work:

  1. Increase the residual herbicide rate, especially of the non-ALS component (Valor, Authority, metribuzin) or add another broadleaf herbicide with marestail activity
  2. Scout the field prior to soybean emergence and apply Liberty + metribuzin, Sharpen + glyphosate, or Gramoxone + metribuzin if small marestail are observed then