Published on:
17:46PM Jun 08, 2009
by AgWeb Staff
Purdue University, Ohio State University and Southern Illinois University recently shared data from a joint 2007-08 glyphosate-tolerant corn timing study. The findings reinforced what many weed scientists (including me) recommend – controlling weeds early in the season protects yield. For example, Iowa State University reports a one day delayed application of glyphosate may cost more than a pre-emergence residual herbicide, depending on crop price and yield potential.
In the study:
- Plots treated with foundation herbicides early in the season performed better than post-only applications.
- The longer weeds were allowed to compete with corn, the less it yielded.
The study showed that applying a pre-emergence herbicide and following up with glyphosate when corn was 12 inches tall yielded 223 bushels per acre. On the opposite end of the spectrum, using no pre-emergence herbicide and waiting until two weeks after corn was 12 inches tall to apply glyphosate yielded more than 40 bushels per acre less.Corn growers across the Midwest use pre-emergence herbicides for a variety of reasons, including better weed control, yield protection, a wider application window, and to control key problem weeds. How have pre-emergence herbicides protected your crop so far this season?
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