White Ash Foliar Damage - Ask Extension
We have a mature White Ash exhibiting some foliar damage. This tree age is unknown, but our home was built in the late 1970s, and I am guessing the tr...
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White Ash Foliar Damage #830939
Asked May 19, 2023, 2:39 PM EDT
We have a mature White Ash exhibiting some foliar damage. This tree age is unknown, but our home was built in the late 1970s, and I am guessing the tree is likely at least that age.
The tree usually leafs out late compared to surrounding maples, and this year is also showing curled, blackened/browned leaves following recent below freezing nights with frost in Essex Junction.
We treated the tree last 2 years with Bayer Advanced Tree and Shrub which has imidacloprid as well as some feeding agents. Applied as a drench at recommended rate of .5oz per inch of circumference (42oz for 84" circumference).
Attached are images of foliar color change and damage. Also attached is questionnaire.
Is this a pest, infection or fungus? Or is this simply damage from frosts? Thanks!
Chittenden County Vermont
Expert Response
Hi. I'm sorry that your ash is not at its best right now. Two things come to mind with regard to your question: environmental stress and emerald ash borer.
1. Based on your description and photos, my guess is that your ash is suffering from the recent roller coaster of warm weather followed by below freezing temperatures. The brown/black leaves are typical of this, as described in this article from Purdue Univ.: https://www.purdue.edu/fnr/extension/cold-injury-to-trees/
”…recent cold mornings resulted in late freeze damage to many trees and shrubs. This damage to newly emerging shoots and leaves follows a few hours of temperatures below the freezing mark. Damage is usually characterized by wilting browning of new growth, particularly leaves and needles. It may take a few days, or until temperatures begin warming again, for damage to become evident….
What can you expect? Typically, the damaged or dead leaves will fall and new leaves will emerge, although somewhat slowly. A reduction in growth and leaf size can be anticipated as well. Just remain calm and wait for the tree to recover. If the tree was vigorous going into winter and had a good store of carbohydrates, it can withstand an environmental hit such as these cold extremes.”
2. Anyone with an ash tree should be aware of the dangers of the emerald ash borer. Your pro-active use of imidacloprid tells me that you are taking steps to protect your tree. Here is a good article that details the use of that pesticide and others: https://extension.colostate.edu/topic-areas/insects/insecticides-used-to-control-emerald-ash-borer-on-residential-shade-trees-5-626/.
More on the EAB can be found at: https://www.vtinvasives.org/land/emerald-ash-borer-vermont
So, most likely, your ash will recover from the frost damage, although it might not leaf out as much as usual this year. Hopefully, EAB's will never be a problem for you!
Best wishes,
1. Based on your description and photos, my guess is that your ash is suffering from the recent roller coaster of warm weather followed by below freezing temperatures. The brown/black leaves are typical of this, as described in this article from Purdue Univ.: https://www.purdue.edu/fnr/extension/cold-injury-to-trees/
”…recent cold mornings resulted in late freeze damage to many trees and shrubs. This damage to newly emerging shoots and leaves follows a few hours of temperatures below the freezing mark. Damage is usually characterized by wilting browning of new growth, particularly leaves and needles. It may take a few days, or until temperatures begin warming again, for damage to become evident….
What can you expect? Typically, the damaged or dead leaves will fall and new leaves will emerge, although somewhat slowly. A reduction in growth and leaf size can be anticipated as well. Just remain calm and wait for the tree to recover. If the tree was vigorous going into winter and had a good store of carbohydrates, it can withstand an environmental hit such as these cold extremes.”
2. Anyone with an ash tree should be aware of the dangers of the emerald ash borer. Your pro-active use of imidacloprid tells me that you are taking steps to protect your tree. Here is a good article that details the use of that pesticide and others: https://extension.colostate.edu/topic-areas/insects/insecticides-used-to-control-emerald-ash-borer-on-residential-shade-trees-5-626/.
More on the EAB can be found at: https://www.vtinvasives.org/land/emerald-ash-borer-vermont
So, most likely, your ash will recover from the frost damage, although it might not leaf out as much as usual this year. Hopefully, EAB's will never be a problem for you!
Best wishes,
Thanks so much Juanita - I was hoping it was "only" due to the crazy weather and not some other pest or disease. Appreciate your reply.
Best,
Lane
