CHARACTERIZATION AND IDENTIFICATION OF COLOMBIAN ISOLATES OF FUSARIUM OXYSPORUM f. sp DIANTHI

Fusarium oxysporum f. sp. dianthi (Fod), with its different physiological races, is responsible for a most devastating carnation disease worldwide. A new wilt disease of carnation cvs Nelson, Toldo and 99-0-81 that appeared in Colombia in 2007, had symptoms different from those usually observed elsewhere on Fod-infected plants. A fungus isolated from infected cultivars was erroneously identified as F. verticillioides on morphological bases. Thus, 10 Colombian fungal isolates were compared with the most widespread physiological races of Fusarium by a molecular approach and two of them were also compared for host susceptibility with four known Fod races. Results led to the conclusion that the Colombian pathogen under study is closely related to Fod. Furhermore, its isolates were identified as race 1, indicating that this race has spread out of the Mediterranean area, where it was confined until now.