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First Report of Brown Felt Blight Caused by Herpotrichia juniperi on Cedrus libani in Turkey

Lebanon cedar (Cedrus libani A. Rich) is an ecologically, economically, and historically important conifer species that currently mainly occurs in the Taurus Mountains in southern Turkey. In former times, extensive forests of this species were also found in Syria and Lebanon. However, because of intensive cutting, burning, and goat grazing, only small populations are left in these countries. Currently, the range of Lebanon cedar covers approximately 600,000 ha in Turkey, including extremely degraded stands and bare karstic land that was previously covered by this species (1). Therefore, efforts to protect existing forests and promote natural regeneration of this endangered tree species were undertaken in recent years. In addition, reforestations were carried out on bare karstic lands to expand the population of Lebanon cedar in Turkey. During disease surveys, carried out in October 2009 in the Mt. Dedegül Region of the western Taurus Mountains (37°36′54″N, 31°20′00″E), a dieback of lower branches and young plants of C. libani was observed at 1,700 to 1,885 m above sea level. The disease often occurred in scattered patches and was most evident near the timberline. Needles, shoots, and twigs of affected trees or entire small trees were covered or completely enmeshed in silky, shining, blackish brown mycelial felts. Symptoms resembled those of brown felt blight, also known as black snow mold, caused by Herpotrichia juniperi and Neopeckia coulteri on various other conifer species (2). For fungal isolation and identification, 18 twig samples from 14 different C. libani trees were collected. Two colonized needles from each twig were transferred to water agar (16 g liter^–1 of agar and 0.1 g liter^–1 of streptomycin) and incubated at 4°C for at least 8 days in the dark. Single hyphal-tip cultures were then established from only one of the developing colonies per twig and transferred to 1.5-ml microcentrifuge tubes containing 500 μl of potato dextrose broth. DNA extraction, directly from the mycelium, was performed after 20 days (3). DNA was amplified using primer pair ITS1 and ITS4 (4) and sequenced. Sequences of two representative fungal isolates from C. libani were deposited in GenBank (HM853976 and HM853977). Comparison of the 18 internal transcribed spacer sequences obtained from C. libani showed 99 to 100% nucleotide identity with those of reference strains of H. juniperi (2) from GenBank and variation among the 18 sequences was <1%, which is within the limits reported in a previous study (2). To our knowledge, this is the first report of C. libani as a new host of H. juniperi. Thus, brown felt blight is considered to have a significant impact on regeneration of C. libani as well as on the survival and growth of seedlings and young trees in the study area.

References: (1) M. Boydak For. Ecol. Manag. 178:231, 2003. (2) M. Schneider et al. Mycol. Res. 113:887, 2009. (3) D. Smith and G. Stanosz. Phytopathology 85:699, 1995 (4) T. J. T. White et al. PCR Protocols: A Guide to Methods and Applications. Academic Press, New York 1990.