Grew up using plain ol’ metachlor it worked. 

then came the “S” version, sliced bread didn’t hold a candle to it, or so we were told.....keep in mind this was a time frame that as we are experiencing now, where pesticide use was scrutinized, closely.

so the mantra in those days was reduction of herbicides either by rate reduction or in some instances cutting back on the application themselves, so this was kinda the era were rate cutting really went mainline.

In the spirit of that, the herbicide companies were really interested in concentrating herbicide A.I.’s because the scale was lbs of product per acre. So in the case of dual, the reduction was almost 20% just by changing the formulation compound, and nothing else.....

there may have been other benefits but that to my recollection was the main one.

so back to the efficacy between the two, we were in those days still incorporating dual, and we thought the “S” formulation was kinda weak on grass and control was inconsistent. In those days very little over-the-top was ever done.

now with just about everything being over-the-top, I see very little difference in control between the two formulations.