The present invention relates to the use of an alcohol consisting of a linear or branched hydrocarbon-based chain having 7 to 9 carbon atoms, substituted with a single hydroxyl group, as a fungicide and/or algicide. It is more particularly directed towards combating the organisms of the family Pythiaceae. It is also directed towards compositions and preparations comprising these novel fungicides and/or algicides, and also the processes for obtaining same and the uses thereof.
