Characteristic spotting of foliage on Norway spruce in Europe, used as an indicator for Waldsterben, was also found and described on foliage of Piceaabies (L.) Karst., P. rubens Sarg., P. glauca (Moench) Voss, P. mariana (Mill.) B.S.P., Abiesbalsamea (L.) Mill., Pinusstrobus L., P. banksiana Lamb., P. resinosa Ait., P. sylvestris L., and Tsugacanadensis (L.) Carr. in northeastern North America. Yellow spotting is restricted to the upper, sun-exposed surface of the needles. These chlorotic spots generally start along ridges of the needles and merge into larger necrotic areas in later stages. It was observed that the number of spots per needle and the number of needles per internode exhibiting such spots are increasing with foliage age. The symptom was prominent on overstory and understory trees in high-elevation spruce–fir forests in Germany and northeastern North America. It was also found in all low-elevation stands sampled.
Distribution of the Balsam Woolly Adelgid in Idaho
