Southworth graduated from the University of Michigan in 1887. She was the first woman plant pathologist to be hired by the USDA, following the recommendation of E. F. Smith. She worked on the diagnosis of plant diseases and made recommendations for disease control on a range of crops. Her most significant contribution to the science of plant pathology was her work on cotton anthracnose and describing the causal agent as Colletotrichum gossypii.
(Submitted for publication in July 2008.)