Birch dieback is a disease of birch trees that causes the branches in the crown to die off. The disease may eventually kill the tree. In an event in the Eastern United States and Canada in the 1930s and 1940s, no causal agent was found, but the wood-boring beetle, the bronze birch borer, was implicated in the severe damage and death of the tree that often followed. In similar crown dieback occurrences in Europe several decades later, the pathogenic fungus Melanconium betulinum were found in association with affected trees,[1] as well as Anisogramma virgultorum and Marssonina betulae.[2]
DeSilva was invoked but never defined (see the help page).