First report of collar and root rot caused by Phytophthora nicotianae on Lycium barbarum

Goji (Lycium barbarum L.) is a Chinese-origin crop recently introduced in Italy. In October 2016, collar and root rots associated with severe twig dieback and foliage desiccation were observed on more than 30% of two-year-old Goji plants in an orchard in Bari province (Southern Italy). A Phytophthora sp. was consistently isolated by plating small pieces of collar and root decayed tissues on a BNPRAH selective medium (Erwin and Ribeiro 1996). All isolates formed white arachnoid colonies on potato-dextrose-agar, with papillate, persistent, pyriform to spherical sporangia of 31–48 × 22–34 μm in size, and globose chlamydospores of 20–32 μm in diameter, both terminal and intercalary singly formed. Oospores were not observed. Phenotypic characteristics matched those of Phytophthora nicotianae (Erwin and Ribeiro 1996).