Eastern Filbert Blight - Ask Extension
I feel ill at the thought of losing my beautiful Contorted Filbert (Harry Lauder's Walking Stick). In the past few weeks there has been a quick progr...
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Eastern Filbert Blight #838501
Asked June 30, 2023, 10:08 PM EDT
I feel ill at the thought of losing my beautiful Contorted Filbert (Harry Lauder's Walking Stick). In the past few weeks there has been a quick progression of leaf death. Today I noticed black stromata on the branches that looks consistent with blight. I am pruning back all of the branches that have visible cankers. I have 3 questions and welcome any additional information that you might have to help my poor shrub.
1. Is there any fungicide that is effective this late in the process that might assist my cutting-back effort?
2. What is the best way to dispose of the limbs in a suburban neighborhood? I don't have access to a burn bin and don't want to risk spreading more spores.
3. If it doesn't make it, would it be unwise to replace it with another Contorted Filbert? Do I need to wait for the fungus spores to clear the area before replanting, and if so, how long?
I appreciate any information that you can offer.
Lorain County Ohio
Expert Response
Thank you for your questions.
I am so sorry that your Contorted Filbert and you are suffering!
I believe you are right about the blight. "Eastern filbert blight is caused by the fungus Anisogramma anomala"
https://www.purduelandscapereport.org/article/contorted-filbert-a-gnarly-problem-plant/
What you having been doing - cutting off the affected areas back to unaffected limbs- is the correct strategy. You need to sterilize your cutters between cuts. On a positive note, the disease is slow moving and is introduced through new growth, so removing affected growth is important. Also removing leaf litter under the tree is suggested.
1. Concerning fungicide, several articles say once the tree has this blight, the fungicides are not always effective. Chlorothalonil is considered a preventative measure, not a cure.
https://hort.extension.wisc.edu/articles/eastern-filbert-blight/
The following article discusses other chemicals and their effectiveness. If you do use a chemical, you must follow directions exactly. https://pnwhandbooks.org/plantdisease/host-disease/hazelnut-corylus-avellana-eastern-filbert-blight
2. As for disposal, the above article recommends burning ( not available for you), deep burying, or chipping. I think deep burying is best for you.
3. I believe replanting in the same spot should not be done for a couple years. Apparently the fungus has a two + year cycle, so when the stromata are evident, it is probably in the second year. https://en.wikipedia.org/wiki/Anisogramma_anomala However, I did not find any definite information on the spores surviving in the soil, only that clearing debris from under the tree was important. If you do replant, I'd use the preventative fungicides and carefully check regularly for signs of the disease.
There are some disease resistant filberts, but not many disease resistant contorted filbert. Corylus avellana 'Contorta' may be resistant according to a nursery that sells it, but I am unable to verify this with any scientific studies.
I hope that your special tree survives with your continues cutting off affected areas.
Sincerely,
I am so sorry that your Contorted Filbert and you are suffering!
I believe you are right about the blight. "Eastern filbert blight is caused by the fungus Anisogramma anomala"
https://www.purduelandscapereport.org/article/contorted-filbert-a-gnarly-problem-plant/
What you having been doing - cutting off the affected areas back to unaffected limbs- is the correct strategy. You need to sterilize your cutters between cuts. On a positive note, the disease is slow moving and is introduced through new growth, so removing affected growth is important. Also removing leaf litter under the tree is suggested.
1. Concerning fungicide, several articles say once the tree has this blight, the fungicides are not always effective. Chlorothalonil is considered a preventative measure, not a cure.
https://hort.extension.wisc.edu/articles/eastern-filbert-blight/
The following article discusses other chemicals and their effectiveness. If you do use a chemical, you must follow directions exactly. https://pnwhandbooks.org/plantdisease/host-disease/hazelnut-corylus-avellana-eastern-filbert-blight
2. As for disposal, the above article recommends burning ( not available for you), deep burying, or chipping. I think deep burying is best for you.
3. I believe replanting in the same spot should not be done for a couple years. Apparently the fungus has a two + year cycle, so when the stromata are evident, it is probably in the second year. https://en.wikipedia.org/wiki/Anisogramma_anomala However, I did not find any definite information on the spores surviving in the soil, only that clearing debris from under the tree was important. If you do replant, I'd use the preventative fungicides and carefully check regularly for signs of the disease.
There are some disease resistant filberts, but not many disease resistant contorted filbert. Corylus avellana 'Contorta' may be resistant according to a nursery that sells it, but I am unable to verify this with any scientific studies.
I hope that your special tree survives with your continues cutting off affected areas.
Sincerely,
