Ophiostoma ulmi

Ophiostoma ulmi is a fungus responsible for Dutch elm disease, a serious illness affecting elm trees. It infects the trees through bark beetles that carry the fungus into the tree’s vascular system. Once inside, the fungus blocks water and nutrient flow, causing leaves to yellow and drop, ultimately leading to the tree’s death. The disease spread widely in the 20th century, decimating many elm populations. Controlling it involves managing beetle populations, removing infected trees, and breeding disease-resistant elm varieties. Ophiostoma ulmi's impact highlights the importance of forest health and disease management strategies.