Susceptibility and lesion development in Scots pine saplings infected with Peridermium pini in northern Finland
Susceptibility of Pinus sylvestris provenances from northern Finland to Peridermium pini and lesion development caused by the rust were investigated by inoculating 768 saplings. Resin-top disease symptoms on the stem including stem swelling, occurrence of spermatial fluid and rust aecia, were recorded over a period of 9 years. The disease incidence was low (3.6%), varying within the range of 0–9.4% among pine provenances and 3.4–3.9% among spore sources in 1994–2002. Aecia were produced for the first time 2–4 years after inoculation, appearing mainly in early June, 2–9 years after inoculation. The aecia ruptured in late July to early August, and the overall sporulation lasted for 1–8 years among the pine provenances. Spermatial fluid was observed regularly in the year prior to aecia development 2–7 years after inoculation. Annual fresh swelling was observed for 1–6 years after inoculation. No statistically significant differences occurred neither between the pine provenances, the spore sources nor the years with regard to all the major disease variables. The results suggest that Scots pine provenances from northern Finland are highly resistant to P. pini regardless of the pine provenance or spore source.
Document Type: Research Article
Publication date: 2003-12-01