Archivio Journal of Plant Pathology

Abstract:

In October 2014, 2% of 50,000 plants of Cereus peruvia- nus florida (family Cactaceae) grown in a nursery of Vallec- rosia (Imperia province, Northern Italy) showed symptoms of a disease characterized by chlorotic and stunted stems and a progressive very slow withering which, however, did not cause death of the plants. A fungus was constantly isolated from symptomatic stem tissues, which produced chlamydo- spores, microconidia and macroconidia typical of Fusarium oxysporum (Leslie and Summerell, 2006) on carnation leaf agar (CLA). Primers EF1/EF2 (O’Donnell et al., 1998) were used to amplify the elongation factor 1 alpha gene (EF1α) of the DNA from a single-spore culture. BLASTn analysis of the amplified product 413 bp in size (GenBank accession No. KT183484) showed 100% homology with the sequence of F. oxysporum LN828036. For pathogenicity tests, three healthy plants of C. peruvianus florida were inoculated with the isolated mycete as described by Talgø and Stensvand (2013). Two days post inoculation, the first rot symptoms ap- peared around the wounds of inoculated stems, from which F. oxysporum was constantly reisolated. Controls remained symptomless. This is the first report of F. oxysporum on C. peruvianus florida in Italy, as well as in the world.