First Report of Phytophthora ramorum on Camellia japonica in Spain

Phytophthora ramorum causes shoot and foliar blight on Rhododendron spp., Viburnum spp. (4), Pieris spp. (2), Kalmia latifolia, and Camellia spp. in several European countries (1-4). In December 2002, we received diseased C. japonica growing in containers from several nurseries in Galicia (northwestern Spain). These young camellia plants had leaves with brown-to-black, water-soaked lesions with diffuse borders that expanded into larger blotches resulting in dead leaves and necrotic lesions on the petioles. Eventually the entire plant wilted and died. Tissue from the leading edge of the lesions was transferred to a selective medium (V8 agar supplemented with pimaricin (10 μg/ml), rifampicin (25 μg/ml), hymexazol (5 μg/ml), and benomyl (5 μg/ml)) and incubated for 3 to 4 days at 20°C in the dark. A Phytophthora sp. was isolated, transferred to carrot piece agar (CPA) (4), and incubated in alternating light. Isolates exhibited coralloid mycelium with concentric rings and a radial growth of 2.5 to 3 mm per day at 20°C. The hyaline-to-yellowish chlamydospores were terminal and intercalary, occasionally lateral, and 24 to 74 μm in diameter. The caducous, sympodial, semipapillate sporangia had a length/breadth ratio of 1.8 to 2.1 and a short pedicel (