Current issue: 54(2)
A Gremmeniella abietina (Lagerb.) race of type A was found to produce pycnidia in cankers of previous year’s shoots (1991) on branches of Scots pine (Pinus sylvestris L.) bearing green needles and living buds in the current-year shoots (1992) with no apparent symptoms of infection by G. abietina. The restricted colonization of green shoots by G. abietina, with only restricted canker development, may indicate that older, slow-growing natural Scots pines of the northern boreal forests resists the fungus well. However, the ability of the fungus to survive and even sporulate in such cankers indicates one way of surviving over consecutive years otherwise unfavourable for it.
Damage on Scots pine (Pinus sylvestris L.) caused by Gremmeniella abietina (Lagerb.) Morelet was assessed in the summer of 1992 in 67 stands in eastern Lapland. The area and severity of damage were smaller and lighter than had earlier been estimated and occurred especially in stands in the first-thinning stage or in middle-age. Significant new infection of 1991 occurred in stands previously heavily infected by G. abietina near Kemihaara river, lake Naruska, the Naruska river, the Tuntsa river and lake Vilma. Fresh damage occurred mainly in the lower or middle parts of the Scots pine canopies.