COMPARISON OF GREMMENIELLA-ABIETINA HISTORICAL DAMAGE TO SCOTS PINES

Fifteen Scots pine (Pinus sylvestris L.) trees that were slightly, mod erately, or severely damaged by Gremmeniella abietina (Lagerb.) Morele t were felled in northern Finland to determine the disease history of the stand. The annual level of damage was determined by counting the s cars and cankers on all the first-order branches. Annual branch leader changes (dead shoots), branch mortality, and attacks caused by shoot beetles, Tomicus spp., were also determined. Most of the G. abietina d amage occurred in the middle and late 1980s. However, the damage occur red at low levels in the stand as early as in the 1940s, demonstrating that the history of the disease followed the established pattern noti ced earlier in eastern Lapland. For slightly damaged trees, most damag e occurred in the mid-1980s, while for their severely damaged counterp arts most damage occurred in the late 1980s.