Fusarium oxysporum is a very common fungus found in soils throughout the world, some strains of which are pathogenic. The only method available at present to control these strains is the use of methyl bromide. INRA scientists in Dijon have developed a biological method to control pathogenic strains of Fusarium oxysporum by clarifying the conditions for the introduction in soil of a strain known for its lack of pathogenicity.