Classical biological control introductions of parasitoids and predators for control of spongy moth occurred from 1905-1997, but two accidentally introduced pathogens have had the greatest impact toward control. Dr. Elkinton began working in a professorial position at the Univ. Massachusetts, the state where the spongy moth was first introduced, in 1980 and very soon after was guiding students and postdocs toward vastly improving our understanding of the epizootiology of the gypsy moth virus, LdMNPV. As publications on the virus from his group began to be published, a second spongy moth pathogen, the fungus Entomophaga maimaiga, was discovered in the northeastern US. Dr. Elkinton did not hesitate and began collaborating on research on the fungal pathogen as well. Research he was involved with eventually compared the biology and ecology of these two pathogens, and his interest in these pathogens has continued in recent years with landscape level studies of the potential for longer distance dispersal of E. maimaiga. Joe’s research approaches have ranged from manipulations of virus, fungus, and spongy moth in the lab and field to modeling, but the focus was always on gaining answers on the latest questions necessary to understand the activity of these pathogens. While neither of these pathogens has been developed as a biopesticide, Joe’s great contributions have led to adoption of these pathogens of spongy moth as model systems for studying the epizootiology of insect diseases.