Take out the (weed) competition

Published on: 12:43PM Feb 01, 2011

Gordon Vail

Just how important are residual herbicides? Consider these facts about early-season weed control in corn with residuals:
  • Delaying weed control until weeds are 2 inches tall, yield reductions of 7 percent—or over 12 bushels per acre—can occur. 
  • Weeds consume nutrients (including nitrogen, phosphorous and water) faster than corn. Studies show that corn plants in weedy fields accumulate only half the nitrogen of crops in clean cornfields at the V2 stage. 
  • The “3:3:1” rule means in three days 3-inch weeds can remove up to 1 inch of water from the field. And competition for soil moisture and nitrogen can result in reduced grain fill, which leads to yield loss.

What other reasons do you have for relying on residual pre-emerge herbicides?

Gordon Vail, Syngenta Herbicide Technical Brand Manager, provides technical leadership for the biological development and labeling of corn herbicides for Syngenta. He holds a bachelor's degree in agronomy and a master's degree in weed science from the University of Arkansas, as well as a doctorate in botany and plant pathology from Purdue University.