Cylindrocladiella peruvianaandPleiocarpon algeriensecausing stem and crown rot on avocado (Persea americana)

During the winter of 2018, 3-years-old trees of avocado (Persea americana) cv "Hass" from Trapani province (Sicily, Italy) showed symptoms of stem and crown rot. Two different fungi were consistently isolated from infected tissues. Morphological characterization and multi-locus phylogenies using five genomic loci (ITS,tef1,tub2,his3, andrpb2) identified these fungi asCylindrocladiella peruvianaandPleiocarpon algeriense. Pathogenicity tests on healthy 5-months-old seedlings and 3-year-old trees of avocado reproduced similar symptoms as those observed in nature, and Koch's postulates were fulfilled for both pathogens. Moreover, the tested fungal isolates revealed a different pathogenic behaviour among two species. Two isolates ofPleiocarpon algerienseresulted more aggressive thanCylindrocladiella peruvianaisolates causing major lesions on young seedlings. This study is the first to report of stem and crown rot on avocado caused byCylindrocladiella peruvianaandPleiocarpon algeriense.