“Top‐dying” of Norway spruce, Picea abies (L.) Karst. with special reference to Rhizosphaera kalkhoffii Bubák

Abstract

AbstractDuring 1974–75 and 1975–76 “top‐dying” foliar symptoms in badly diseased Norway spruce began appearing on current year's needles as early as mid summer and autumn whereas in healthy or mildly affected trees they appeared later, in late winter and spring. In all trees however the maximum rate of needle loss occurred just before and during the flushing period. The disease affected current as well as second year needles. Needle loss took place during the whole year at different rates for different tree‐health categories. The total amount of needle loss increased significantly with worsening health status of trees.