Winter annuals continue to increase as tillage is reduced.
Generally, winter annuals do not represent a major threat to corn and soybean production and thus do not require special tactics for control. However, last fall's extended warm temperatures have allowed these weeds to accumulate more biomass than typical. Some fields, particularly in the southern third of Iowa, may benefit from targeted herbicide applications to control these weeds. If winter annuals are found on more than 25 percent of the field, it is likely that some effort to control them will be beneficial. The question is whether to make a separate application specifically targeting the winter annuals or to wait and deal with them at planting.