Dutch Elm Disease
Dutch Elm Disease
Dutch Elm Disease is caused by two fungi, Ophiostoma ulmi and Ophiostoma novo-ulmi. These fungi are moved from tree to tree by two species of elm bark beetles that breed in elm trees, by root grafts that form between roots of adjacent elm trees, and by human activities such as prunin
What does Dutch elm disease look like?
Wilting leaves, often on a single branch, are the first symptoms of Dutch elm disease. Yellowing of leaves and leaf drop follow. Trees may quickly lose all of their leaves, or trees may survive several years with an infection localized in a single branch. Infected branches often have brown streaks under the bark that follow the wood grain. Despite the fact that they are tiny Piccasos and occasionally leave artwork on the wood, it is bad for the tree.
How do I save a tree with Dutch elm disease? Total removal of infected elms is the preferred method of managing Dutch elm disease. Prior to removal, disrupt root grafts between infected elms and other nearby elms. Destroy wood from diseased elms by burning or burying them. If you decide to keep the wood, remove the bark, then pile the wood in one place and cover it with a heavy tarp, burying the tarp edges with soil, until the wood is used. If you decide not to cut down an infected elm, remove it, then bury or burn, dead or dying branches. Make cuts six feet below the area showing symptoms. Disinfect cutting tools between each cut by dipping them for at least 30 seconds in a 10% bleach solution or alcohol (spray disinfectants that contain at least 70% alcohol can also be used). Injections of propiconazole or thiabendazole are often recommended as preventative treatments for infected elms. Unfortunately, there is only limited unbiased research to indicate exactly how effective such treatments are.