Southeast Asian workers cut shiitake mushrooms at Phillips Mushroom Farms. The mushroom industry in Chester County, Pa., has relied on several waves of immigrant workers, beginning with Italians in the late 1800s.

Southeast Asian workers cut shiitake mushrooms at Phillips Mushroom Farms. The mushroom industry in Chester County, Pa., has relied on several waves of immigrant workers, beginning with Italians in the late 1800s.

Southeast Asian workers cut shiitake mushrooms at Phillips Mushroom Farms. The mushroom industry in Chester County, Pa., has relied on several waves of immigrant workers, beginning with Italians in the late 1800s.

Southeast Asian workers cut shitake mushrooms at Phillips Mushroom Farms. The mushroom industry in Chester County, Pa., has relied on several waves of immigrant workers beginning with Italians in the late 1800s.