Sirococcus clavigignenti-juglandacearum (butternut canker) is a fungus that causes a lethal canker disease of Juglans cinerea (Butternut) trees. It is also known to parasitize other members of the genus Juglans (walnuts) on occasion, and very rarely other related trees including Carya (hickories).
Pycnidiospores are released during rainy periods. When the spores make contact with wounds or broken branches, they germinate and penetrate deep into the tree to produce cankers. Infection hyphae typically penetrates through the parenchyma phloem intracellularly but they can also penetrate intercellularly through uni and multiceliate xylem ray cells and paranchyma cells. Later, the fungus will produce mycelial mats of stroma and mycelial pegs.
Stroma mats will produce uni or multilocular pycnidia. Inside the pycnidia are branched and unbranched conidiophores with two-celled pycniospores, which later are ejected from the pycnidial ostiole.
Additionally, the stroma will produce a peg of interwoven mycelium. These pegs put pressure on the outer peridium of the host bark, which exposes the pycnidia below. These pegs also produce pycnidia that are smaller than the pycnidia in the stroma. While different in size, the spores produced are identical.
Recent reports have shown that the fungus can be internally seed-borne, so seeds should be subjected to intense quarantine protocols; most especially if destined for plantings where the disease is not already established.
Genetic diversity of butternut (Juglans cinerea) and implications for conservation.(RAPID COMMUNICATION / COMMUNICATION RAPIDE)(Report)
Apr 01, 2008; Abstract: The management of threatened and endangered species can be improved by understanding their patterns of genetic...