What’s wrong and how to save my Pinus echinata? #851203

Asked September 25, 2023, 4:02 PM EDT

The needles are browning and falling off from the bottom up to the top of the plant. It’s only green at the top, and very scraggly. It’s in part sun, near Black Walnuts and other deciduous trees, on the edge of riparian woods. The soil is clay with humus mixed in from the trees, we don’t mow them. Thank you

Montgomery County Maryland

Expert Response

Given the pattern of browning and the vulnerability of certain pines to this condition, our prime suspect is an infection called Diplodia Tip Blight. Trees stressed by environmental conditions, including high heat and drought, are more susceptible to infection. The linked pages provide more information about this widespread disease and what indicators you can look for (which might require a little bit of magnification to see well) to help confirm this assessment, though you could also have the tree diagnosed by a certified arborist. Some arborists are employed by tree-care companies but others consult independently.

Removal of all fallen needles and cones under the tree may reduce the spore abundance that would otherwise keep re-infecting the tree, though the other recommended approach to prune off all dead branch tips is impractical for a tree of this size. Similarly, while fungicides can sometimes suppress infection, they cannot cure existing disease (or reverse its impacts), nor would they be practical to use on a tree of this scale, though you could see what an arborist proposes, bearing in mind that fungicide use might have side effects for other organisms exposed to its residues.

Pines do not replace foliage lost on older wood, so bare sections where there are dead branches will probably remain without foliage for the life of the tree. If too much of an eyesore and/or the tree is too declined, you may be able to replace it with another species. While other conifers can also contract Diplodia, many pine species seem to be particularly vulnerable, unfortunately. If the tree's eventual death (whether from this or other factors) and fall won't hurt anything, it's also fine to keep (this disease is so ubiquitous you won't be exposing much that hasn't already been exposed) since dead and dying trees provide lots of good wildlife value.

Mira Talabac Replied September 26, 2023, 10:55 AM EDT

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