Dutch Elm disease - Ask Extension
We are loosing the Elm trees one by one in our backyard to Dutch Elm Disease. Arborist from Davey said they can’t save our since it also propagates ...
Knowledgebase
Dutch Elm disease #872060
Asked June 07, 2024, 12:45 PM EDT
We are loosing the Elm trees one by one in our backyard to Dutch Elm Disease. Arborist from Davey said they can’t save our since it also propagates through root and our trees are close to each other. I see other infected trees around the neighborhood. Is there anything OSU can do to save the remaining elm trees. Note that these are natural woods.
Delaware County Ohio
Expert Response
Hello,
The scourge of Dutch Elm Disease has been in the U.S. since the 1930's. While progress has been made in treating individual trees with mechanical and chemical disruption of the root grafts, as well as the treatment of the elm bark beetle which vectors DED, there are additional factors that make it difficult to manage.
Dutch Elm Disease (DED), a fungal pathogen, spreads through the root grafts, as you mentioned. The disease initially is spread by European and North American elm bark beetles that can live hidden under tree bark but also can move freely between the trees.
So, to protect uninfected trees, the root grafts have to be cut, which in a woods or forest setting would be nearly impossible. The beetles also need to be treated with insecticide, another costly and difficult task, given their ability to move freely but also live hidden under the tree's bark. Another complication is that the wood of any infected tree must be completely removed and destroyed. Every piece of an infected tree must be removed or the bark beetles, possibly surviving in the leftover tree material, will in time, move on to the other trees. In other words treating trees in a woods setting is a costly, complicated and difficult to accomplish successfully.
There are trees that survive Dutch Elm Disease. OSU, MSU and other universities, working with the United States Forestry Service, are studying and propagating seed from trees that have survived DED. One such research facility, run by the USDA Forestry Service is a tree farm called the Delaware Northern Research Station in Delaware, Ohio. At the research facility, DED resistant trees are being propagated, studied, and tested for viability. This research is where universities like OSU are concentrating their resources in order to preserve the future existence of the elm tree.
But another problem in this complicated situation has emerged. In addition to the difficulty of treating diseased trees there is another disease that will infect elms that have already been weakened by DED. This disease is called Elm Yellows. Elm Yellows is caused by a phytoplasma, or a type of bacteria, which destroys a tree's phloem. Phloem is the substance which transports food manufactured in the leaves and carries it to the other parts of the tree. Elm Yellows can kill an elm tree in as quickly as a year's time, given the right environment.
Scientists are finding that Elm Yellows is targeting trees already stressed by DED and also infecting elms that are stressed by adverse environmental factors such as drought, excessive water, and poor soil. The American elm, Ulmus americana, which has shown some resistance to DED, has been found to have no known resistance to Elm Yellows.
The OSU Extension office in Delaware County might be able to help you further with ideas for resources concerning the treatment and management of Dutch Elm Disease in your community. The Extension staff may be aware of programs that fund conservation efforts for elm trees.
I have listed a link below for the OSU Delaware County Extension office website which will give you their contact information.
Also listed below are links for articles concerning DED and Elm Yellows. Please write back if you should have more questions about either of these tree diseases.`
Thanks for asking Ask Extension.
Betsy B. - MGV
https://woodlandstewards.osu.edu/sites/woodlands/files/d6/files/pubfiles/3308%20dutch%20elm.pdf
https://ohioline.osu.edu/factsheet/plpath-tree-04
https://bygl.osu.edu/node/1666
https://bygl.osu.edu/node/484
https://senr.osu.edu/sites/senr/files/imce/images/lauerandrew_805529_56855588_USFS.pdf
https://delaware.osu.edu/
The scourge of Dutch Elm Disease has been in the U.S. since the 1930's. While progress has been made in treating individual trees with mechanical and chemical disruption of the root grafts, as well as the treatment of the elm bark beetle which vectors DED, there are additional factors that make it difficult to manage.
Dutch Elm Disease (DED), a fungal pathogen, spreads through the root grafts, as you mentioned. The disease initially is spread by European and North American elm bark beetles that can live hidden under tree bark but also can move freely between the trees.
So, to protect uninfected trees, the root grafts have to be cut, which in a woods or forest setting would be nearly impossible. The beetles also need to be treated with insecticide, another costly and difficult task, given their ability to move freely but also live hidden under the tree's bark. Another complication is that the wood of any infected tree must be completely removed and destroyed. Every piece of an infected tree must be removed or the bark beetles, possibly surviving in the leftover tree material, will in time, move on to the other trees. In other words treating trees in a woods setting is a costly, complicated and difficult to accomplish successfully.
There are trees that survive Dutch Elm Disease. OSU, MSU and other universities, working with the United States Forestry Service, are studying and propagating seed from trees that have survived DED. One such research facility, run by the USDA Forestry Service is a tree farm called the Delaware Northern Research Station in Delaware, Ohio. At the research facility, DED resistant trees are being propagated, studied, and tested for viability. This research is where universities like OSU are concentrating their resources in order to preserve the future existence of the elm tree.
But another problem in this complicated situation has emerged. In addition to the difficulty of treating diseased trees there is another disease that will infect elms that have already been weakened by DED. This disease is called Elm Yellows. Elm Yellows is caused by a phytoplasma, or a type of bacteria, which destroys a tree's phloem. Phloem is the substance which transports food manufactured in the leaves and carries it to the other parts of the tree. Elm Yellows can kill an elm tree in as quickly as a year's time, given the right environment.
Scientists are finding that Elm Yellows is targeting trees already stressed by DED and also infecting elms that are stressed by adverse environmental factors such as drought, excessive water, and poor soil. The American elm, Ulmus americana, which has shown some resistance to DED, has been found to have no known resistance to Elm Yellows.
The OSU Extension office in Delaware County might be able to help you further with ideas for resources concerning the treatment and management of Dutch Elm Disease in your community. The Extension staff may be aware of programs that fund conservation efforts for elm trees.
I have listed a link below for the OSU Delaware County Extension office website which will give you their contact information.
Also listed below are links for articles concerning DED and Elm Yellows. Please write back if you should have more questions about either of these tree diseases.`
Thanks for asking Ask Extension.
Betsy B. - MGV
https://woodlandstewards.osu.edu/sites/woodlands/files/d6/files/pubfiles/3308%20dutch%20elm.pdf
https://ohioline.osu.edu/factsheet/plpath-tree-04
https://bygl.osu.edu/node/1666
https://bygl.osu.edu/node/484
https://senr.osu.edu/sites/senr/files/imce/images/lauerandrew_805529_56855588_USFS.pdf
https://delaware.osu.edu/
