The goal of weed management is to maximize corn yield potential. Killing weeds is just a necessary step to achieve that goal. The critical part in reaching this goal is to kill the weeds on time. A herbicide program can work extremely well to control weeds in the right situation.
Many corn fields that are sprayed post-emergence may not have been sprayed on time. Studies have shown that corn yield is lost when weeds are sprayed after they exceed 4 inches. Weeds can also be extremely competitive with corn for nitrogen. Even though it is possible to regain the lost corn yield by applying high rates of nitrogen to the soil, the high cost of nitrogen makes this a much costlier option. Effective weed control is certainly more cost effective than over applying nitrogen just to feed the weeds.
The key is timely weed management to protect corn yields. A pre-emergence or residual herbicide greatly increases the window for post-emergence applications of glyph sate. Glyph sate can be applied early before weed competition begins. Corn growers just need to understand the risk of not getting all their corn fields sprayed on time if spraying total post-emergence programs. Early applications increase the chance that later flushes of weeds might need a second application. To avoid retreating, residual herbicides can be tank mixed with a glyph sate premix that includes a residual component can be used.
Weeds can be effectively managed in corn fields. The key is to implement a program that controls weeds from the start or gets it done on time. Spraying herbicide before weeds reach 4 inches is the cut off to achieving proper weed management in your corn fields. If weeds have not presented themselves yet, preventative spraying is all that is needed. You don’t want weeds to destroy your valuable corn crop!