In both cases the people making the reports thought the worms were soybean loopers. It is easy to tell the two caterpillars apart because loopers have two pairs of prolegs on the abdomen while the green cloverworm has three pairs. Loopers are fairly lethargic, but green cloverworms hop around quickly when disturbed.
Green cloverworm larvae near Ralls
Typical defoliation in soybean caused by green cloverworm
Fortunately the green cloverworm is only a leaf feeder in soybean and it does not damage pods. For alfalfa here is a quote the Oklahoma guide, "These defoliators are rarely a significant problem in established alfalfa, although seedling stands can be heavily damaged by their feeding." However, if there are enough of them present they can cause defoliation, which in turn will reduce the amount of nutrients the plants can store for overwintering.
For soybeans, University of Tennessee has good list of insecticides in their publication here. Oklahoma State University has control suggestions for alfalfa here.
