Published online by Cambridge University Press: 31 May 2012
In November 1958 a Douglas-fir (Pseudotsuga menziesii var. glauca (Beissn.) Franco) Christmas tree was received at the Missoula Forest Insect Laboratory with a note that it was infested with an insect that might be causing “Christmas-tree blight.” This term is commonly used by the trade to refer to any condition of foliage that might affect salability or price of Christmas trees. Several types of foliage-feeding insects, as well as fungi or poor site conditions, may cause “blighted” or discolored needles; however, on this tree the infestation proved to be caterpillars tunneling in the bark.