Since immemorial times scholars and landowners have been concerned to fight diseases attacking wheat. Interest was particularly strong in France during the Enlightenment, although no effective solution was found to prevent the damages caused by one of the most infectious of them – the wheat bunt – until the beginning of the 19th century. Isaac-Bénédict Prévost (1755-1819), a Swiss naturalist, carried out some experiences in Montauban (Southern France) between 1798 and 1807, which revealed the cause of the disease as well as an efficient way to fight the relevant microscopic fungus. The discovery was completely underestimated by the Institut de France, thus bringing about a great delay in French agriculture. The study of this validation process will enable us to apprehend the mechanisms pertaining to a striking case of a blockage of scientific knowledge in imperial France as well as a possible route taken by a scientific discovery from its birthplace to the main national agency responsible for spreading knowledge, that is the Institut.