Ace the ISA Certified Arborist Test 2025 – Branch Out and Conquer Your Career!

Dutch elm disease is a well-documented and significant disease affecting many species of elm trees. It is caused by a fungus (Ophiostoma spp.) that is transmitted by elm bark beetles. The disease disrupts the tree's vascular system, leading to wilting, yellowing of leaves, and ultimately, tree death. The impact of Dutch elm disease has been profound, particularly in urban areas where elms were once a dominant landscape tree, making it a critical concern for arborists and urban forestry.

While other diseases listed, such as root rot, black spot fungus, and powdery mildew, do affect trees and plants, they encompass a broader range of species and are not as specifically associated with trees in the way that Dutch elm disease is with elms. Root rot can affect various plants and trees but is not a disease exclusive to trees. Black spot fungus is primarily known for its impact on roses rather than trees in general, and powdery mildew is a common fungal issue that affects a variety of plants, including shrubs and herbaceous plants, not being tree-specific. Thus, Dutch elm disease stands out as a notable and specific threat to tree health, particularly in the context of disease management for arborists.