Below is that nasty seed. The range of seed color is a reflection of biodiversity with the species. This biodiversity could be either due to genetic or somatic polymorphism. In North America the black and darker seed usually is associated with the weedy types, while the lighter brown and cream color seed is from the crop. Because the seed will often stay with the roots, this can be used in field ID, especially when the you are unsure if it is wild proso millet or woolly cupgrass.
Nothing can stop a determined wild proso millet plant.
Besides prolific and dormant seed waiting to take over a corn field, wild proso millet dominates because it has an unusually well developed herbicide resistance system. Once I applied 99 lbs. It grew bigger than the untreated plants, possibly because it used the rapidly degraded herbicide as a nitrogen source. The weeds always win. The picture on the left also shows a whitish soybean cotyledon injured by frost early in the season.