%0 Research article
%T Analysis of Cronartium flaccidum lesion development on pole-stage Scots pines
%A Kaitera, Juha
%D 2000
%J Silva Fennica
%V 34
%N 1
%R doi:10.14214/sf.641
%U https://silvafennica.fi/article/641
%X Historical and current lesion development and sporulation of Cronartium  flaccidum was investigated in a stand of artificially seeded pole-stage  Pinus sylvestris in northern Finland. An average of 6.5 lesions  developed per infected tree, most of them occurring on a minority (25%)  of the trees. During the monitoring period of five years, fresh aecia  appeared mainly in 7–10-year-old shoots, the age of the shoots bearing  aecia varying between 3–20 years. Aecia appeared for the first time most  frequently in 5–10-year-old shoots. Infection waves occurred, whereas  lesions were formed most frequently in shoots formed in various years  through the 1980s. After the lesions started to sporulate, sporulation  in most lesions that finished sporulating during the monitoring period  lasted for 1–2 years. The aecia in between 47% and 59% of the infected  shoots developed annually over a longer length in proximal direction  than in distal direction next to the previous year’s infection. The  aecia-bearing distal part of the shoot was longer in between 19% and 37%  of the shoots.