A DTN report says the winter annual often pops up in no-till corn and soybean fields. It’s native to the U.S. and is found from Texas east into Alabama and Florida, and up the east coast from Georgia through Virginia, and back west all the way to Nebraska. The plant is poisonous to grazing animals like cattle, horses, sheep, goats, and to humans as well.
Burndown herbicides are used in the spring when the plants are smaller, but that’s not an option in forage crops and in wheat. The plant is most poisonous during the bud-to-flower stage, and most likely to affect the first cuttings of alfalfa. It doesn’t typically regrow after the first alfalfa cutting of the season. Bales that wind up with a lot of butterweed in them should immediately be discarded.