Citrus > Citrus General Discussion

Spots on tangerine tree leaves - please help ID

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Calusa:
Can anyone tell me what is causing these yellow spots on a tangerine tree I found at a nursery?








UNDERSIDE OF LEAF

Calusa:
I think I may have found the answer - citrus variegated chlorosis.

I'll take 2nd opinions though. Thanks

Galatians522:
It looks like Citrus Canker to me. This article would seem to indicate that the specific sub-species that causes Citrus Verigated Chlorosis is not currently found in Florida.

https://www.google.com/url?sa=t&source=web&rct=j&url=https://crec.ifas.ufl.edu/extension/plant_pathology/citrus_variegatedc_chlorosis.shtml&ved=2ahUKEwjRx66GxsrwAhWITt8KHfLlB-oQFjAPegQIEhAC&usg=AOvVaw0VkVp7j08gxqB1B5EpEhXo&cshid=1621043138442

Here is another link with info about Citrus Canker. In either case, the tree should likely be distroyed if it is at a nursery.

https://www.google.com/url?sa=t&source=web&rct=j&url=https://edis.ifas.ufl.edu/publication/PP116&ved=2ahUKEwij5Z30xMrwAhVBm-AKHayoAkYQFjAcegQINBAC&usg=AOvVaw1bThZvZMFVDCkfcT46nD0s&cshid=1621042517473

Calusa:
Good catch on the CVC. It would be an extremely rare occurrence in Florida.

I do not believe it's Canker either. There are no lesions or depressions on the upper surface of the leaves, and the underside does not have the same appearance as Canker.

Greasy Spot? Some other fungal disease, or insects such as mites or scale?

orangedays:
This looks like muscle scale, Lepidosaphes beckii. Try scratching off the brown marks on the leaf, if they detach from the leaf and are filled with soft wet mater then you can be sure. Its a persistent problem in the south east. The scale is often in the surrounding environment so you may have to continually treat for it. If you don't treat it, it slowly kills small plants.  However if the tree is small enough to cover with spray, neem oil and spinosad work really well so long as you spray every two weeks for several months.  There is also imidacloprid systemic insecticide. This works well against the scale but it is very toxic systemic so its recommend after blooms and as a last resort.

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