First report of Heterobasidion annosum in Cyprus

Black pine (Pinus nigra ssp. pallasiana) is indigenous in Cyprus, occurring on Mount Troodos and covering an area of about 2000 ha. In June 2003, wood and bark samples were collected from stumps of black pine. A Heterobasidion species was isolated from the inner bark surface of two stumps in two different sites more than 3 km apart, at altitudes of about 1600 and 1700 m. Both isolates were heterokaryotic as concluded from the presence of clamp connections in the mycelium. In mating tests, using homokaryotic tester strains from Europe and North America, the species H. annosum sensu stricto (European P group) was identified (Niemelä & Korhonen 1998). This fungus infects primarily pine hosts. One of the Cyprus isolates, deposited in the culture collection of the Finnish Forest Research Institute (Nr 04001), was used in pathogenicity tests with one-year old potted black pine seedlings, using the method of Swedjemark & Stenlid (1995). Three months after inoculation 2 plants out of 15 were dead; in living plants the extent of lesion of the inner bark varied from 10 to 60 mm. The fungus was consistently re-isolated from dead and living plants.

This is the first report of Heterobasidion in Cyprus and the southern most record of H. annosum s. str. in Europe (34° 56´ N). Although the number of isolates from Cyprus is small and no basidiocarps were observed, the fungus appears to be native in this natural forest. One reason for the scarcity of the fungus seems to be the lack of logging operations in this forest during the last 50 years, with most of the stumps examined being very old. No signs of disease were observed and it would appear that H. annosum does not have a significant impact on the black pine forests of Cyprus. This pathogen is also not a major problem in the black pine forests of southern Greece, although it was found to be quite common there (Tsopelas & Korhonen, 1996).

Acknowledgments

The authors are grateful to Kari Korhonen, Finnish Forest Res. Inst., for tests with the North American strains and verification of the identity of the fungus.