Articles
AN IMPROVED METHOD TO EVALUATE FUSARIUM OXYSPORUM F.SP. GLADIOLI PATHOGENICITY
The host list of (Fog) covers different Iridaceae. To evaluate the pathogenicity of fungus agent through unique, stable and repeatable test is important because the presence of saprophytic strains is profuse even within the own corm lesions.
Seven different pathogenicity tests (Table 1) were compared using nine isolates representatives from varied symptom situations (Table 2). By a simple index, pathogenic capacity (PC) (Table 3) four methods were inadecuate and the other three gave not significatively different results (Table 4). The more simple method (test 1, table 4) consisted in the inoculation of Friendship 4/6 cormels, punched with a needle and incubated during 24 hours in a suspension of fungal spores and mycelium and planted on soil container.
This test gave a clear cut separation between pathogenic and saprophytic strains with few intermediate cases (4,6%) (Table 6). The test is repeatable and shown stable in different culture conditions (Table 7).
The examination of a wide collection of isolates from all the gladiolus symptoms and some other from Iridaceae confirm the essential pathogenicity similarities of the strains of Fog.