01785nas a2200241 4500008004100000022001400041245008400055210006900139260002600208300001400234490000700248520106700255653001901322653001801341653001801359653002401377653001901401100001901420700001701439700001701456700001501473856005501488 2003 eng d a1365-305900aEvaluation of root damage to English walnut caused by five Phytophthora species0 aEvaluation of root damage to English walnut caused by five Phyto bBlackwell Science Ltd a491–4950 v523 a

The pathogenicity of five species of Phytophthora to English walnut was studied in a greenhouse experiment. Phytophthora cinnamomi was the most aggressive species, causing severe root rot and seedling mortality. The other species tested, P. cambivora, P. citricola, P. cactorum and P. cryptogea, did not induce visible crown symptoms on seedlings 2 months after inoculation. Some strains of P. cambivora and P. cactorum also caused taproot damage to seedlings. All except one of the tested isolates caused significant necrosis of fine roots and a significant reduction of root weight compared with noninoculated seedlings. Reduction of above-ground plant development was not statistically significant. While P. cinnamomi is well known as an aggressive primary pathogen of English walnut, the other species of Phytophthora may act as predisposing factors to walnut decline, affecting root system development and increasing host vulnerability to environmental stress.

10aEnglish walnut10aJuglans regia10apathogenicity10asoilborne pathogens10awalnut decline1 aVettraino, A M1 aBelisario, A1 aMaccaroni, M1 aVannini, A uhttp://dx.doi.org/10.1046/j.1365-3059.2003.00864.x01408nas a2200241 4500008004100000022001400041245010900055210006900164260002700233300001200260490000700272520068900279100001900968700001800987700001601005700001501021700001601036700001601052700001301068700001501081700001501096856005501111 2002 eng d a1439-032900aOccurrence of Phytophthora species in oak stands in Italy and their association with declining oak trees0 aOccurrence of Phytophthora species in oak stands in Italy and th bBlackwell Science Ltd. a19–280 v323 a

Soil-borne species of Phytophthora were isolated from 19 of 30 examined oak forest areas in Italy. The frequency of isolated Phytophthora spp. (35.2%) was significantly correlated with soil pH and longitude of the sites. Eleven Phytophthora species were detected. Phytophthora cambivora, P. cinnamomi and P. cactorum were recovered from sites in central and southern Italy whereas P. quercina was isolated in the northern and central part of the country. Phytophthora citricola occurred all over Italy. Phytophthora quercina was the only species significantly associated with declining oak trees.

1 aVettraino, A M1 aBarzanti, G P1 aBianco, M C1 aRagazzi, A1 aCapretti, P1 aPaoletti, E1 aLuisi, N1 aAnselmi, N1 aVannini, A uhttp://dx.doi.org/10.1046/j.1439-0329.2002.00264.x00466nas a2200145 4500008004100000022001400041245006500055210006400120260002600184300001400210490000700224100001900231700001500250856005500265 2003 eng d a1365-305900aScotch broom: a new host of Phytophthora megasperma in Italy0 aScotch broom a new host of Phytophthora megasperma in Italy bBlackwell Science Ltd a417–4170 v521 aVettraino, A M1 aVannini, A uhttp://dx.doi.org/10.1046/j.1365-3059.2003.00839.x01366nas a2200169 4500008004100000022001400041245012200055210006900177260002500246300001000271490000700281520081700288100001901105700001601124700001801140856003801158 2008 eng d a0815-319100aPhytophthora ramorum infection of coast live oak leaves in Californian forests and its capacity to sporulate in vitro0 aPhytophthora ramorum infection of coast live oak leaves in Calif bSpringer Netherlands a72-730 v373 a

Coast live oak (Quercus agrifolia) is a known host for Phytophthora ramorum, the casual agent of sudden oak death in California, with symptoms expressed as necrotic stem cankers. In the forest, leaves on two saplings in California were found to be infected with P. ramorum and these were associated with infected bay laurel (Umbellularia californica) trees. Coast live oak leaves supported sporulation and produced chlamydospores in vitro. This is the first report to identify foliage of coast live oak as a source of infection of P. ramorum in the forest and its confirmation in in vitro inoculations.

1 aVettraino, A M1 aHüberli, D1 aGarbelotto, M uhttp://dx.doi.org/10.1071/AP0708502678nas 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

During 2006 and 2007, declining mature beech trees (Fagus sylvatica) 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). Phytophthora 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 Phytophthora cactorum, 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 P. cactorum could be reisolated from all lesions. Controls showed no symptoms. P. cactorum is widespread in declining beech forests in central Europe (1). In Italy, P. cactorum 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 P. cactorum being associated with declining beech trees in Italy.

1 aVettraino, A M1 aJung, T1 aVannini, A uhttps://forestphytophthora.org/references/first-report-phytophthora-cactorum-associated-beech-decline-italy