02678nas a2200169   4500008004100000022001400041245008100055210006900136260001200205300001600217490000700233520211000240100001902350700001202369700001502381856011202396       2008                        eng d  a0191-291700aFirst report of Phytophthora cactorum associated with beech decline in Italy0 aFirst report of Phytophthora cactorum associated with beech decl  c12/2008  a1708 - 17080 v923 a<p>During 2006 and 2007, declining mature beech trees (<em>Fagus sylvatica</em>) were recorded in two stands in the Natural Park of Monti Cimini in central Italy. Symptoms included crown thinning and the presence of bleeding lesions on the main roots and lower stem. Incidence of decline was approximately 5%. Samples of necrotic bark tissue were collected, cut into 5 mm long segments, plated on PARPNH, and incubated at 20°C (1). <em>Phytophthora</em> isolates were obtained from necrotic tissues of 25% of the sampled declining trees. Colonies were rosaceous on potato dextrose agar (PDA) and homothallic. Papillate, ovoid-to-obpyriform, caducous sporangia (mean 38 × 26.2 μm) were produced in soil extract. Oospores were plerotic (mean diameter of 22 to 32 μm) and antheridia paragynous. Optimum growth temperature was 23 to 25°C, minimum 6 to 8°C and maximum 30 to 33°C. A portion of the internal transcribed spacer sequence has been deposited in the NCBI database (GenBank Accession No. FJ183724). A BLAST search of the NCBI database revealed <em>Phytophthora cactorum</em>, Accession No. EU194384, as the closest match with 100% sequence similarity. Pathogenicity of two isolates, PFE3 and IFB-CAC 38, collected from distressed beech trees was tested using a soil infestation test (10 beech seedlings per isolate and control) and an under the bark inoculation method (10 twigs per isolate and controls, wounded and noninoculated taken from a declining beech tree) (2). After 2 weeks at 20°C, twigs and seedlings inoculated with each isolate developed extensive necrotic lesions around the inoculation sites and the collar, respectively, and <em>P. cactorum</em> could be reisolated from all lesions. Controls showed no symptoms. <em>P. cactorum</em> is widespread in declining beech forests in central Europe (1). In Italy, <em>P. cactorum</em> occurs in soils of chestnut and oak forests and was isolated from collar and root lesions of declining walnut trees (3). To our knowledge, this is the first report of <em>P. cactorum</em> being associated with declining beech trees in Italy.</p>1 aVettraino, A M1 aJung, T1 aVannini, A  uhttps://forestphytophthora.org/references/first-report-phytophthora-cactorum-associated-beech-decline-italy