Possible Oak Fungus - treatment recommendations? #780663

Asked January 23, 2022, 11:38 AM EST

Have attached two photos of two wounds on opposite sides of large Oak Tree - Oak Tree Wound 1 - IMG_9256.jpg and Oak Tree Wound 2 - IMG_9257.jpg Neighbor suggested it was possible fungus and I am writing to ask regarding recommendations for possible treatment, or any nutritional additions to the wound or on ground surface. Would a light bleach solution be useful on the surface or injected/squirted into the wounds? Or some other nutrients or fungicide if this is a fungus? How do you determine what it is? Should I take a 'scrapping' up to the center on Harry Truman Parkway in Annapolis? We have already lost some oaks due to Declining Oak Disease and certainly don't want to lose this one too. Appreciate any perspectives and advice you may offer.

Anne Arundel County Maryland

Expert Response

We cannot say what caused the wound on the trunk and there is nothing to do. No chemical controls or bleach are recommended. This may be slime flux for which there is no treatment. 

We suggest that you wait until the tree leafs out in the spring. Look for new shoot growth, any dieback, thinning in the canopy, etc. If you notice decline, we do recommend that you consult with a certified arborist for an onsite diagnosis.  An arborist can assess the situation and recommend practices to support the tree's health if needed. You can find a certified arborist in your area using this online directory:

Here is more information. Unfortunately, many mature oak trees in Maryland are in decline. We have been getting reports of declining oaks from all over the state for the last two years or so. There is no single cause. For such a situation to occur over many species of oaks and a wide area, it is likely due to a combination of environmental factors and even the age of the trees. The excessively wet weather of 2018 and early 2019 may have contributed to root decline in some. White oaks in particular are intolerant of water-logged soils. Root stress can lead to early fall coloration, browning, leaf drop, and eventual dieback. Periods of drought also put stress on the trees, and when they are stressed by unfavorable environmental conditions year after year, they become more susceptible to pests such as ambrosia beetles. Some oaks also are dying of Bacterial Leaf Scorch (not common on white oaks but it is an issue in red oaks located in urban and suburban areas).

Here are our web page links on why oak trees are declining


Marian Hengemihle Replied January 24, 2022, 11:36 AM EST
Thanks much for the insights and recommendations shared Marion.

We will watch for the condition in the spring and may contact an arborist locally.

All the best -


On 1/24/2022 11:36 AM, Ask Extension wrote:
Richard A. Perrin Replied January 24, 2022, 12:12 PM EST

You are welcome.


Marian Hengemihle Replied January 24, 2022, 12:18 PM EST

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