Every growing season, there is a critical point when weeds threaten yield in soybean fields. Stop weeds before they reach it.

That critical period to control weeds is before they emerge and threaten the yield potential of young soybean plants. Soybean yield can be reduced by 1 percent every day weeds aren’t controlled, according to research at Iowa State University.

The best time to control weeds is before they are out of the ground, says Joe Armstrong, field scientist, Dow AgroSciences. When weeds are allowed to compete with the crop for essential nutrients, yield potential is threatened and once yield is gone it can’t be regained, he says.

“Though the window may seem short to protect yield, there are preventive steps growers can take to reduce early season weed competition,” Armstrong said. “Growers can no longer rely on glyphosate and postemergence applications alone. This spring, growers should use a preemergence herbicide such as Sonic herbicide to get ahead of weeds.”

By applying only postemegrence herbicides, growers carry a high risk of early season yield loss. Because the critical period of weed control occurs early in the season, using only postemergence herbicides narrows the application window. Preemergence control allows the postemergence application to be delayed until the crop canopy has developed so that weeds emerging after the application are not a concern.1

“A residual herbicide applied preemergence keeps working weeks after application so developing crops don’t compete with weeds for essential nutrients, moisture and sunlight,” Armstrong said.

The residual herbicide touted by Dow AgroSciences is Sonic. A residual herbicide sets up a second pass of herbicide applications by keeping weeds smaller and easier to control longer.

“If weeds are controlled before and during the critical period of weed control, the risk of losing yield will greatly diminish,” Armstrong said.

For more information related to Sonic and Surveil co-pack, visit BattleWeeds.com.