First report of Phytophthora cryptogea on common cypress

The common cypress (Cupressus sempervirens) is widespread throughout the Mediterranean area where it plays an essential role in the characterization of the landscape, and is widely used for its aesthetic value and timber production, for protection of soils from erosion and for windbreaks. In 2009 and 2010 in two young ornamental plantations in Tuscany and one nursery in Umbria (central Italy), some specimens of C. sempervirens cv. Bolgheri showed symptoms of sudden yellowing of the crown starting from the basal portion, followed by death of the plants. The incidence of diseased trees was around 10-15% at all sites. A Phytophthora species was isolated from the rhizosphere and from roots of symptomatic and dead plants on selective medium PARPH. Morphological characteristics were registered on 5-day-old cultures grown on carrot agar. Ribosomal DNA regions (ITS1, 5.8S rDNA and ITS2) were amplified, sequenced and compared to sequences of known Phytophthora species from GenBank. Morphological and molecular results identified this species as Phytophthora cryptogea. A pathogenicity test was conducted using 3-years-old ramets of several clones of C. sempervirens grown in pots containing soil inoculated with sterile millet seeds colonised separately by two isolates of P. crytpogea. For each P. cryptogea isolate twenty plants were inoculated and 10 untreated plants were used as controls. Reduced growth of the roots and crown wilting followed by death of the plants were observed, thus confirming the pathogenicity of P. cryptogea on C. sempervirens. This is the first report of P. cryptogea on C. sempervirens.