Inoculation of young pine seedlings with Peridermium pini from north-east Scotland

Seedlings of Pinus sylvestris, P. nigra ssp. laricio, and P. mugo vars mughus, rostrata and pumilio were inoculated at their cotyledon stage with aeciospores of Peridermium pint from north-east Scotland. Infection was determined by the presence of both mycelia and haustoria in free-hand or paraffin sections. In the second growing season, infected seedlings showed symptoms such as stem-swelling, development of spermogonia and aecia, and death. In a second experiment, young P. sylvestris seedlings from seven seed sources collected in Great Britain were inoculated and the infection was examined after 6 weeks. In the samples of 50 seedlings from each source, 30-70% seedlings were infected.