Knowledgebase

Is this fire blight? #874272

Asked June 23, 2024, 11:35 AM EDT

I noticed this first on 5/21. About a third of the leaves looked droopy. My back yard is wooded and I don’t want this spreading, but I’m not clear what’s going on or whether it’s contagious. First two photos are today, third is 5/21.

Montgomery County Maryland

Expert Response

It's hard to see the symptoms clearly, and part of the plant diagnostic process involves knowing what the host plant is, since that can be key to determining which pests or diseases affect that plant. We can't quite tell from the photos what type of tree this is...is it a Magnolia? (The foliage looks reminiscent of Magnolia.) If so, Fire Blight does not affect them; it only infects some members of the rose family, like crabapple and pear. Other types of blight or different infections can cause similar symptoms, none of which can be cured after disease has set in, but some of which cause more long-term plant damage than others. If within reach, can you share some close-up images of the damage, where dying growth meets still-healthy-looking growth? And do you know what type of tree this is? We can try to narrow-down potential causes with that information.

Miri
Plantnet says it’s black tupelo. See if these photos help. Thank you! 

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The Question Asker Replied June 25, 2024, 9:29 AM EDT
Thank you for the additional photos, but given the low lighting, it's hard to see enough detail, like if there's a canker where the dying tips meets still-healthy wood. (Cankers tend to look like discolored, sunken/shriveled, or otherwise abnormal sections of bark where a fungus or bacteria infected the wood.)

We rarely see damage this significant on Black Tupelo (Nyssa sylvatica). Unfortunately, we don't have a concrete diagnosis from the photos, but we do suggest you contact a certified arborist who can assess the tree in person. Some of the larger tree companies have their own diagnostic lab in case they submit samples for pathogen testing, but companies that don't have their own lab could submit samples to nearby labs since the UMD pathology lab is temporarily closed (see the linked page for alternatives).

We can say that Fire Blight is not responsible for the symptoms if this is a Nyssa. Was any digging done in the tree's root zone (anywhere outside the branch tips or closer to the trunk) in the past year or so? Is there any visible damage to the trunk itself, like large scars or decaying holes from old branch removal?

If physical root damage isn't responsible, our working theory is perhaps severe Botryosphaeria canker, since it affects a very wide range of plants that are stressed (often by drought, which we experienced last year). Verticillium Wilt can cause wilting, collapsed foliage, but usually the damage from those infections is more widespread than the scattered tips visible currently. This might be something a lab can test for, however.

The pebbly, bumpy texture to some leaves (visible in the foreground of your last image) is commonplace and not concerning, as they are a type of mite gall which don't cause the tree any notable harm.

If samples are sent to a pathology lab, we would be interested to learn what the testing reveals, if a pathogen is detected.

Miri

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