Dual or Metolachlor is absolutely fine pre or post. I suspect you are dealing with a combo that has something others that you need to spray pre only. Fierce xlt, Sonic, zidua pro, etc. So many options out there & each cocktail has a list of which herbicides are in it. Label will tell u to be certain like above.
*Regular 2,4-d on non-enlist beans needs at least 5 days sprayed before planting.
Pre’s that can be sprayed pre & post & make a good mix…. Or run with second pass if wanted…
Metolachlor (dual II) or acetochlor (warrant),
Prowl h20
I’ll run enlist beans (resistant to Gly, enlist 2,4-d & Liberty)…. I’ll burn down with Gly, 2,4-d & either fierce xlt (very careful on rates) or zidua pro. If u want to spray/plant same day- technically need to use enlist 2,4-d.
Second pass: Liberty, enlist 2,4-d, metolachlor & one more like prowl. 2 pass that’s wicked & I’ve never had an issue with seeding cover crops later. Is it an overkill for plots? Yes. But, over larger fields, it’s a game changer on weed control & reduced spraying.
I would say weed suppression is equally helped when: 1) PH is right 2) cover crops are used 3) weed control & cover crops have been done effectively for several years - gets easier.
All this seems complex but it’s pretty simple when get swing of it. A good pre-emergent down & spraying weeds post (with another pre) when they are small will yield great results.