Speckled lenticel spots (SLS) – an emerging postharvest disease on apples in South Tyrol (Northern Italy)

Abstract: Symptoms of speckled lenticel spots (SLS), also known as Ramularia spots, were
first observed in South Tyrol (Northern Italy) in 2012 on apples after long-term conservation in the cold storage. Microbiological isolation and subsequent molecular analysis based on the
rRNA encoding gene region identified Ramularia eucalypti as causative agent of this
postharvest disease. This fungus has already been described to cause a similar damage pattern on pears (2011) and apples (2012) in the Piedmont region (Italy). However, since 2019, a notable increase of Ramularia spots, also referred to as dry lenticel rot, has been observed in South Tyrol. Thus, a first genetic analysis of fungal isolates, originating of various orchards was performed. An alignment with the sequence data deposited in GenBank revealed mostly R. glennii as pathogen. Currently, sequence analysis based on further gene loci is ongoing and might give a more detailed insight on the Ramularia species present on apple in South Tyrol.