Sphaerulina musiva is distributed in northeastern North America sympatrically with the native eastern cottonwood P. deltoides, on which the disease is limited to a leaf spot symptom. These endemic leaf spots on P. deltoides are believed to constitute a source of inoculum for hybrid poplar plantations. S. musiva has sometimes been reported on Tacamahaca poplars indigenous to North America (P. trichocarpa and P. balsamifera) and on their hybrids. For example, in 2006, a high incidence of stem infections caused by this fungus was observed on P. balsamifera in a plantation within its native range in northern Alberta. S. musiva leaf spots have also been observed on willow trees, as Salix lucida spp. lucida.
