Plum tree blackening leaves, what's this disease?

9 years ago

We live coastal southern California (Oceanside) and this tree was planted before we got the house. I was told it was a plum tree but it hasn't had any fruit yet so I'm not sure.

Before it started to get cold (around Aug/Sep), its leaves started to wilt and turn brown. Shortly after, they started to blacken and fall off, with a fair amount of sap seeping from their "joints."

Originally thought it was a watering issue, so increased watering and noticed new growth from the top branches after a few months but the leaves are still all blackening, turning crisp and falling off.

Other leaves have many small brown spots on them, see picture in the next post.

The new growth has no leaves but has noticeably less sap.

Is this a disease?

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Comments (4)

exxpi
Original Author
9 years ago
Here is a picture of the brown spots and some of the sap.
ronalawn82
9 years ago
exxpi, I think that there is more than one issue.
Some of the brown spots look like 'pustules' - and I cannot advance a possible casual agent.
Some soft scales (mealy bugs?) might be active at the leaf nodes; but they do not appear in enough numbers to account for the amount of sooty mold (if indeed the cause) of the black coloration or deposit as widespread as your comments suggest.
I cannot tell the size of the tree but I would clean it up even if I had to use a ladder.
A forceful jet of water from a hose would blast off most insects and all dead leaves. Apply soap water with a sponge/brush to any remaining soft scale and / or sooty mold.
The cold weather will help you to have a 'bug free' tree as spring comes along.
I hope that no 'hard scales' are present; you will have to pick or scrape them off.
I am not as familiar with the plum tree or with southern California as perhaps, I should be.
However I attach this LINK for your consideration.
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Kimmsr
9 years ago
Have you talked with the people at your local University of California Cooperative Extension Service office?

Here is a link that might be useful: UC CES
ken_adrian Adrian MI cold Z5
9 years ago
when did you get the house ..

from the last pic.. the pruning cut.. makes me think its a brand new planting ... straight from the seller .. meaning.. a shipping cut ...

if so ... we dont know if it was properly planted .. properly watered ... or anything ...

it is rather surprising.. how a stressed tree .. is attacked by all kinds of problems... but unless you solve the stress .. then solving all the secondary problems is useless ...

lets have a pic of the whole ... and then see what we can intuit ...

it might be simpler.. and cheaper.. to be done with it ... i never understand.. spending 20.. 30.. 50 dollars on remedies.. for a tree not worth 20 bucks ... sometimes.. its just easier to start over.. if in fact you want a plum... which is subject to all kinds of problems.. like black know and gummosis ... on older trees .. i gave up on plum decades ago ... just a PIA tree ...

also.. there is a very active fruit forum ... no reason not to try both forums ...

ken