First report of Gremmeniella abietina on Pinus halepensis in Spain

A dieback caused by Gremmeniella abietina was first seen on Pinus halepensis, south of Palencia, northwest Spain in late 1999. The symptoms of the disease included drying up of needles and branches with some distortion of terminal twigs, resulting in dieback and death of trees. Affected trees occurred in five out of a total of 43 stands that were examined. Around three to four dead trees were found in three of these five stands.

Twigs and shoots samples from diseased trees were surface sterilized and plated on potato dextrose agar plates at 15°C. The conidial state Brunchorstia pinea was identified from these samples using cultural and morphological characters, later confirmed by Dr. Jarkko Hantula of the Finnish Forest Research Institute using genetic markers. Abundant pycnidia containing typical spores of B. pinea occurred in the bark and developed on stems and needles taken from damaged trees and maintained in humid chambers.

The disease has been reported on P. halepensis in Turkey (Spaulding, 1961) and Italy, where Pinus pinea was also susceptible (Barbacovi et al., 1979). This species was unaffected by the disease in mixed stands with P. halepensis in Palencia. Possibly this is because the growing conditions for P. halepensis are less favourable. There is a clear link between such conditions and the incidence of the disease in other pine species (Witzell and Karlmann, 2000).

Martínez (1933) recorded G. abietina earlier on P. pinaster in Spain, but this is the first record on P. halepensis of a disease that has been responsible for significant losses to pines in Europe and North America (Sinclair et al., 1989). Further effort is now required to determine its impact on pines in Spain.