No abstract

Four species of the destructive forest pathogen Heterobasidion annosum sensu lato (s.l.) are present in Europe: H. annosum sensu stricto (s.s.), H. abietinum and H. parviporum are native species, while H. irregulare is a non‐native invasive species currently reported only in Italy, yet recommended for regulation throughout Europe. In this study, real‐time PCR detection tests were developed for each of the four species, which can be used simultaneously or individually thanks to probes labelled with species‐specific fluorescent dyes. The different performance criteria of each assay were evaluated, and it was determined that they were theoretically capable of detecting amounts of DNA corresponding to 311, 29 and 29 cell nuclei in H. annosum s.s., H. irregulare and H. parviporum, respectively. The specificity of each assay was assessed with a wide set of strains. Real‐time PCR tests successfully detected Heterobasidion species from 36 fruiting bodies taken from the forest, as well as from artificially inoculated or naturally infected wood samples. The multiplex real‐time PCR assays developed in this study could have practical applications both in forest management and in phytosanitary monitoring.

The incidence of garlic rot has constantly increased in France since the early 2000s.To set up an efficient method of garlic protection against this disease, we have clarified its aetiology. This was achieved by surveying garlic from the two main French basins of garlic production over 3 years. Fungi were isolated from 5,493 garlic cloves belonging to pink, purple, and white garlic types. Sequencing of the translation elongation factor 1α gene of 1,171 strains revealed that 94% of the strains belonged to the species Fusarium proliferatum and 6% belonged to F. oxysporum. The pathogenicity of both species on garlic was confirmed by artificial inoculations and reisolations. There was significantly more F. oxysporum in garlic cloves with symptoms coming from the southeast basin (9.44%) than from the southwest basin (2.76%). This study confirms that garlic rot is present in pink, purple, and white types. However, pink type garlic harbours F. oxysporum significantly less frequently (1.59%) than white (9.39%) and purple (7.34%) types. Sequencing of rpb1, rpb2, ITS, and IGS regions of a subsample of strains revealed that there is little genetic diversity in the French population of F. proliferatum.