Fungal pathogen (Cryphonectria parasitica)

Cryphonectria parasitica is a fungal pathogen responsible for causing chestnut blight, a disease that affects American chestnut trees. It infects the bark and cambium layers, leading to cankers (lesions) that disrupt nutrient flow, causing the tree to weaken, die back, or die entirely. The fungus spreads through spores, often via wind or contact. This disease has historically decimated native chestnut populations in North America, significantly impacting ecosystems and forestry. Management includes removing infected trees, applying fungicides, and breeding blight-resistant chestnut varieties.