Lemon tree with tiny black spots on leaves: please help

6 years ago

last modified: 6 years ago

My potted lemon and a neighbor's in-ground lemon have started to have tiny black spots on the front of the leaves. The spots appear to be on the front side, although they are visible on the back when the leaf is in the light. The leaves eventually turn yellow but hang on for a long time. The spots do not look like sooty mold. They do not look like greasy mold. Is this something new? Aside from removing affected leaves, what should we do?

Example A-1. Leave that is turning yellow, still attached to the tree.

Example A-2. Back of leaf A-1 but now detached from tree.

Example B-1. Front of leaf attached to tree, mostly green but starting to yellow.

Example B-2. Back of leaf B-1.

Example C-1. Another spotted leaf (right below a very new lemon)

Example C-2. Back of leaf C-1.

Featured Answer

Silica

6 years ago

It has the looks of Citrus Black Spot, a disease that affects all commercial citrus cultivars to some degree, and lemons are especially susceptible. When the disease first appears in a new area, it usually does so on lemons. Black spot occurs in subtropical regions with summer rain fall. Contact your local county advisor.

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Comments (6)

HU-867910465
Original Author
6 years ago
last modified: 6 years ago
Thank you, Silica. I will contact the local Extension service.

Meanwhile I found this on Citrus Black Spot: https://www.aphis.usda.gov/aphis/ourfocus/planthealth/plant-pest-and-disease-programs/pests-and-diseases/citrus/citrus-black-spot/citrus-black-spot . The description of the spots does not quite match what I am seeing and fortunately the fruit has not been affected.

My lemon tree started as a volunteer. Its parents may have been commercial citrus cultivars but it grew from a seed spread by the wind or wildlife. I wasn't sure what it was when it first appeared in my garden but it was too close to a rosebush so I put it in a small pot. That was about 10 years ago. I have 2 other store-bought lemon trees but they are more than 40 feet away and so far neither has spotted leaves.
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HU-163156813
6 years ago
Hi! I have a small potted lemon tree that has recently developed black spots very similar to yours. Did you have success in figuring out the problem?
HU-867910465 thanked HU-163156813
Melissa Mulvaney
5 years ago
I think it’s a fungal infection. I got it too. I was told to use liquid copper and baking soda. Has anyone tried this??
HU-867910465 thanked Melissa Mulvaney
HU-867910465
Original Author
5 years ago
Sorry, HU-163156813, not to have seen your message sooner. Alas, I haven't figured anything out.

Thank you Melissa Mulvaney. I don't now anything about liquid copper and baking soda for plants. Will look into it!
François B
4 years ago
I have the same issue, did someone found a way?