Resumo. The treehopper Aetalion reticulatum (Linnaeus, 1767) (Hemiptera: Aetalionidae) was found infesting three baru trees (Dipteryx alata Vogel) in Brasilia, Distrito Federal, Brazil. Aetalium reticulatum is considered an important pest and has been reported to damage various agricultural and forest crops. However, this is the first report of this insect in baru, a native tree species from the Brazilian Cerrado, thus expanding the insect’s known host range.