A Novel Strawberry Disease Associated With Leaf Spot, Crown Rot, and Root Rot Caused by Neopestalotiopsis rosae in Italy

In the spring of 2023 in Eboli and Caserta (Campania, southern Italy), strawberry plants (var. Marimbella) grown in organic open fields showed an outbreak of a severe and unprecedented decline (disease incidence reaching > 80%) associated with root rot, crown rot, and leaf spot and closely resembling symptoms reported previously in other countries for Neopestalotiopsis spp. infection. Therefore, the present study was undertaken with the aim of determining the aetiology of this serious disease. Fungal isolates were obtained from symptomatic strawberry plants and investigated in detail for molecular identification. Phylogenetic analysis was conducted by amplifying and sequencing three DNA barcodes: the internal transcribed spacer (ITS) region of rDNA, the beta-tubulin (tub2) partial gene, and the translation elongation factor 1 alpha (tef1) partial gene. Symptoms observed in the field were replicated in pathogenicity tests, conducted by inoculating strawberry (var. Marimbella) leaves, fruits and plants, thus satisfying Koch's postulates. Phylogenetic analyses identified the causal agent as Neopestalotiopsis rosae. To our knowledge, this is the first report of the emerging and serious fungal pathogen N. rosae infecting strawberry in Italy.