Once thought to be an innocent bystander to field crop production, common ragweed can "drastically reduce soybean yields," according to University of Nebraska-Lincoln research. In dense populations, the loss was shown to be 40-76%.
Even with new dicamba-resistant soybeans, pre-emergence, residual herbicides are needed to mitigate yield loss due to weed competition, provide a longer time for soybean to establish, and reduce selection pressure for weeds resistant to post-emergence herbicides.
Sulphur cinquefoil is a perennial forb and aggressive invasive species that establishes quickly in disturbed areas and over-grazed sites. Prevention and, if necessary, timely identification and management are the best routes to containing this invader.
With many wheat fields planted later than normal due to rain, stands are not as competitive with weeds and younger plants may be susceptible to herbicide injury, making a good weed management plan even more important this year.
With temperatures beginning to warm up, now is a good time to manage weeds such as field pennycress, downy brome, mustards, cheatgrass, and shepherd's purse in dormant alfalfa without risking plant injury.
Nebraska Extension specialists in the ag media discussing challenges of early season weed control, the good and the bad of cover crop insects, irrigated wheat production, and improving use efficiency of applied organic nitrogen.
Results from a 2017 weed management trial on glyphosate-resistant ragweed indicated two applications were often more efficient and cost effective than either three applications or one application of herbicide.