Exserohilum echinochloae grows on the leaves of a plant in Bangladesh. That plant was formally classified as a species of another plant that has higher specie than Populus.
Panicum (panicgrass) is a large genus of about 450 species of grasses native throughout the tropical regions of the world, with a few species extending into the northern temperate zone. 
Populus is a genus of 2535 species of deciduous flowering plants in the family Salicaceae, native to most of the Northern Hemisphere. 
 It was formerly classified as a species of "Panicum". 
 Found in Bangladesh, where it grows on the leaves of "Echinochloa colona", it was described as new to science in 1984. 
