I don't see how spraying less of a substance than you're allowed is unsafe. There are a lot of farms where reduced rates will be very effective. The hot new sprays are all post-emerge. So are the newest herbicide-resistant programs. Post-emerge is also user friendly.
Growers can focus first on planting, then worry later about putting down their weed control.
They don't have to pray for activating rains, and they can actually see their weeds before they spray. Corn growers, however, must pick their way through a dizzying list of 80 registered post-emerge sprays. For soybean growers, there are 40. As well, every post spray has its weaknesses and peculiarities, says Bill Deen, weed scientist at Ridgetown College. Despite company claims, every spray is weak on at least a few weeds.