Archivio Journal of Plant Pathology

Abstract:

Serious losses occur in cultivated (Eruca vesicaria) and wild (Diplotaxis tenuifolia) rocket varieties infected by Fusarium oxysporum f.sp. raphani in north-western Italy. Forty-four varieties of cultivated and wild rocket were chosen for resistance tests carried out under glass from June 2004 to June 2005, for the evaluation of resistance to Fusarium wilt. Roots of 30-day-old plants were inoculated by dipping in a conidial suspension (106 CFU/ml) of the pathogen. Three trials were conducted using as inoculum strain Fus Ruc 9A isolated from a wild rocket variety and strain Fus Ruc 13/03, isolated from cultivated rocket; both were strains of Fusarium oxysporum f.sp. raphani. Fus Ruc 9A was found to be the more virulent, and the majority of rocket varieties were susceptible or highly susceptible to it. Some rocket varieties showed resistance to Fus Ruc 13/03. In an overall disease index evaluation, varieties 7/02, 2/03, 5/03, 6/03, 7/03, 11/03, 12/03, 20/03, 24/03, 6/04, and 13/04 were at least partially resistant. The data obtained indicate that only a few of the rocket varieties available in Italy are resistant to Fusarium wilt. Moreover, differences in the host range of the two strains of F. oxysporum f.sp. raphani used suggest the presence of different races of the pathogen.