Johnson adds that the residual you might get next spring does depend on weather factors. "You can get some residual control into spring once temperatures warm up for weeds to germinate, but that gets difficult to predict," he notes. For example, depending on weather conditions, a fall-applied residual could give you control as late as the first two to three weeks of April.

Owen adds that the decision to treat doesn't have to be a whole-farm issue. "Scouting is important, if you're not scouting there's no need to consider treating," he says. "If you have 5,000 acres of ground, scout and treat those that have real problems with mairestail and other winter annuals. Compartmentalize and use precision when making weed management decisions."

One piece of good news? "There is no shortage of active ingredients to consider nless you have evolved herbicide resistance issues in the marestail popluations, which again emphasizes the need for scouting," Owen adds.

The decision tree with this story walks through the decision choices to consider if you're pondering a fall weed control pass.