I want to save my PPO chemistry for that last chance post spray. That takes Valor out of the Pre program. Prowl seems to be the best choice around here for a pre but it needs some help to get to that early to mid June cut-off date for FlexStar. I added Metribuzin. Part of the Metribuzin went on tank mixed with the Prowl and incorporated. Part got a separate trip pre-emergent. Although the pre-emergent application had better control, getting it on before a rain and before the soybeans emerge is a stressful gamble. The flip side is the tank mixing/pre-plant option limits the use of row cleaners. I had to halt soybean planting and switch to spraying this spring to get it on in time.

As far as using PPO's post in soybeans, I think one needs to go with a modified 21 day rule. I start looking for weeds 14 days after planting. As I approach 21 days I really look closely. I spray at 28 days whether I see weeds or not. If I was @21 days and rain was forecasted I would spray even if no weeds were visible.

As far as which PPO, Generic FlexStar seems to fit. It has a longer residual than Cadet or Cobra and is cheaper. It'll take down larger Waterhemp than Cadet (4 leaves not 4 inches) and offers some residual. IMO Cadet only works on Waterhemp that is too small to tell for sure that it's Waterhemp. If I did not get a chance to spray FlexStar and the Waterhemp got to 3" I would switch to Cobra. I keep some in stock as buying Cobra in season gets expensive.