Pawpaw “Leaf Scorch” Cause?

Some of my mature pawpaw trees are recently developing what I’m calling leaf scorch.
See pictures.
It essentially begins as little brown spots that become a larger and larger area (though not in the way that fungal spots coalesce).
There is no yellowing or any other leaf symptom that precedes it.
It’s not every leaf on the tree, just some. And not just the leaves that get the most sun.

I have a lab diagnosed magnesium deficiency but that usually shows as interveinal chlorosis and usually shows up later.
I feel like this scorch could nevertheless be another symptom OR some other nutrient issue.

Anyone else seen this?

Anyone have any ideas?

Is that happening with more than one variety?

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Yes - each of my trees is a different variety or seedling. :disappointed:

I’ve not seen this on my paw paws. However, from dealing with other trees, my guess is disease of some sort. That doesn’t look like a nutrition deficiency, certainly not magnesium. I’ve never seen insect damage that looked anything like that, and it doesn’t look like physical damage from wind, birds, falling branches, etc… If it’s not insects, not physical, and not nutrition, by process of elimination you’re left with disease.

[quote=“TrilobaTracker, post:1, topic:37904”]
It’s not every leaf on the tree, just some. And not just the leaves that get the most sun.
[/quote] Lots of fungi thrive in the shade. And if your trees are like mine, they tend to become very dense over time, reducing air circulation and keeping the leaves damp for long periods of time.

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I was brainstorming about that too and it definitely could be disease. Maybe bacterial since doesn’t really look like any of the major fungi.

I definitely have had issues with black spot and phyllosticta in the past and have mysteriously lost 3 trees over time.

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Phylloticta or some other disease is my guess. Here’s some info from DISEASES, PESTS, & BUTTERFLIES — Peterson Pawpaws “Various leaf spots commonly infect pawpaw leaves and fruits: a complex of Mycocentrospora asiminae , Rhopaloconidium asiminae, and Phyllosticta asminae. Symptoms include tan spots with dark brown borders on leaves, and dark brown to black superficial spots on the fruit.” The Phyllosticta on leaves pictures I’ve seen do look similar to yours.

Were any trees cut down nearby, or something new reflecting light? Looks like sunburn, the damage has a pattern that doesn’t look like disease to me.


WE have talked
if you believe in lack of Mag
Only guess is a quick dose epson salt of a few tree’s small small dose though
see if it improves .
Good advise Haldog

another thing ampersand he said his was not in full sun,
but other wise he could experiment with a spray bottle for mistinf the ;eaves
to create humidity
you never know it could be the weather I do not know but we (in IL not TN) has had no rain

Have you Tracker of the paw ?

It’s pretty common in really hot areas and rare or unknown in cooler areas. It seems to be caused by too much heat. The tree withdraws water from leaves to protect the roots. Most of the leaves will have some exposure to sun but some won’t.

It would be nice to know where (geographically) people are reporting this.

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oops wrong topic supposed to be Frost tolerant Pawpaw seedlings.

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Sorry Off topic.

@ampersand - no, no alteration to the sunlight reaching these trees.
@haldog - i have had phyllosticta before and it actually has unique/noticeable appearance different from this situation.

@castanea - I think this is the most plausible explanation. We have had a relatively sudden increase in temps and humidity coupled with little rainfall.

Out of curiosity, are you referring to pawpaw specifically or just fruit trees in general?

Pawpaws. I grew them for 25+ years in the very hot California central valley.

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This is super helpful - thank you!