What is Dutch elm disease? How can I tell if I have an infected tree? As a leading provider of tree removal services in Winnipeg, MB, the licensed arborists at Mitchel’s All Season Tree Experts can help you figure out all you need to know about infected wood and tree pests.
Trees improve the resale values of residential, commercial, and industrial lots, so we empathize with property owners dealing with infected wood. An American Elm Tree has considerable value, as its bark is naturally resistant to moisture damage. It remains a vital source of wood for constructing farm buildings, boats, and furniture, so losing a single tree can strike a blow in any seasoned real estate investor’s portfolio.
Below, our licensed arborists explain how Dutch elm disease kills trees and what tree owners can do to prevent infections.
What is Dutch Elm Disease?
Dutch elm disease has been responsible for the deaths of more than 40 million American elm trees, making it one of the greatest threats to deciduous forests on the East Coast and in the Midwest. It is still one of the most invasive tree diseases in Minnesota, where you can find it in nearly every city.
How can you prevent Dutch elm disease from spreading from an infected tree to a healthy one? It helps to understand how this devastating tree disease travels and multiplies.
Dutch elm disease is the layman’s term for the Ophiostoma novo-ulmi fungus, one of the most aggressive tree-killing pathogens in North America. Many non-invasive Ophiostoma subspecies appear in the Rocky Mountains region, and many scientists thought it originated there.
However, botanists began tracing its entry into the United States in the 1930s. They tracked its roots to Northwest Europe, estimating its starting point sometime in the early 1910s.
The British Forestry Commission, through botanist Tom Peace, was able to track the spread of the Dutch Elm Disease throughout the 1920s as it ravaged the United Kingdom. It caused the deaths of more than 40% of European elms. In the mid-1940s, tree deaths waned but snowballed into a larger and more destructive wave after the late 1960s.
Hylurgopinus rufipes, or the elm bark beetle, is native to the United States. The European elm bark beetle, or the Scolytus multistriatus, is the cousin responsible for the disease’s spread throughout Europe. Dutch elm disease spreads from tree to tree by hitching onto these beetles’ exoskeletons, including their boring and feeding organs.
The Dutch Elm Disease Cycle: Borers to Bark
So, Dutch elm disease enters healthy trees through boring beetles that create incisions in small branches, attached twigs, and tree bark. The pathogen can also spread through root grafts from infected trees.
Beetles transfer the pathogen to the sapwood, which spreads to the xylem that is responsible for moving nutrients up and down through the bark. The infection will then spread from vascular tissues into the roots, disrupting the transport of moisture and nutrients. As the tree wilts, the beetles use tissues from dead trees to form breeding galleries, and the cycle continues.
Signs Your Tree Might Have a Dutch Elm Disease
Dead or dying trees reduce the curb appeal of homes and businesses, but there are much bigger concerns as ecosystems face the loss of large sections of forest. Here are a few signs your tree might have Dutch elm disease:
- Leaves shrivel and die while remaining on a diseased branch
- The inner bark is a dark brown colour when peeled back
- Branches drop prematurely