[The sugar cane blight of the 1860s: science applied to agriculture].

The Imperial Instituto Fluminense de Cultura (Fluminense Imperial Institute of Agriculture) encouraged debate with a view to eradicating the blight that devastated sugar cane plantations in the State of Bahia. Rural landowners, government officials and men of science participated in the discussions. The article presents the context of the sciences applied to agriculture, especially agricultural chemistry and the repercussions of the 'discoveries' of Justus Liebig in Brazil. The debate at the Imperial Instituto about the sugar cane blight was analyzed, together with the ideas espoused there and the characters involved in the issue. The procedures and solutions presented are studied, as well as the formation of knowledge networks around the agricultural sciences, which was in the process of institutionalization at the time.