Anisogramma anomala. Eastern Filbert Blight is a fungal canker disease caused by Anisogramma anomala on several filbert species. The most common ornamental filbert cultivar grown in landscapes is a European Filbert, Corylus avellana ‘Contorta’, also called Harry Lauder’s Walking Stick. Filberts are also sometimes called hazelnuts. Early symptoms include wilted or dead leaves hanging from infected branches. Distinctive rows of parallel elongate black lesions are often visible along infected twigs and branches. These perennial lesions elongate each year and will eventually girdle and kill the infected branch. The disease cycle may take 2-3 years after infection to cause dieback. There appear to be eastern and western strains of the pathogen.