Author Topic: Spots on tangerine tree leaves - please help ID  (Read 297 times)

Calusa

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Spots on tangerine tree leaves - please help ID
« on: May 14, 2021, 07:45:26 PM »
Can anyone tell me what is causing these yellow spots on a tangerine tree I found at a nursery?








UNDERSIDE OF LEAF


Calusa

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Re: Spots on tangerine tree leaves - please help ID
« Reply #1 on: May 14, 2021, 08:10:35 PM »
I think I may have found the answer - citrus variegated chlorosis.

I'll take 2nd opinions though. Thanks

Galatians522

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Re: Spots on tangerine tree leaves - please help ID
« Reply #2 on: May 14, 2021, 09:49:01 PM »
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

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Re: Spots on tangerine tree leaves - please help ID
« Reply #3 on: May 15, 2021, 12:21:09 AM »
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

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Re: Spots on tangerine tree leaves - please help ID
« Reply #4 on: May 17, 2021, 10:37:51 AM »
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.

orangedays

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Re: Spots on tangerine tree leaves - please help ID
« Reply #5 on: May 17, 2021, 10:45:57 AM »
Now that I've looked a a lager image of the underside of the leaves. I don't this is muscle scale. Normally the scale also settles along the petiole and the petioles and stems look clean on these leaves. The muscle scale also leave hard brown muscle shell shaped marks that are not integrated into the leaf but on the top of it. Maybe it is some type of fungus.

Millet

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Re: Spots on tangerine tree leaves - please help ID
« Reply #6 on: May 17, 2021, 02:50:57 PM »
I'm not 100 percent sure what it is, but most likely a copper fungicide spray will take care of it.

Laaz

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Re: Spots on tangerine tree leaves - please help ID
« Reply #7 on: May 17, 2021, 03:09:55 PM »
It looks a lot like old spider mite damage.

Calusa

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Re: Spots on tangerine tree leaves - please help ID
« Reply #8 on: May 17, 2021, 06:38:23 PM »
Well these replies certainly have me feeling better! The thought of a deadly disease had me kinda worried. I'll shoot it with some copper and keep any eye out for pests.

Thanks fellas!

Lovetoplant

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Re: Spots on tangerine tree leaves - please help ID
« Reply #9 on: May 26, 2021, 08:19:21 PM »
Second to millet.  My tangerine had the same problem like your tree.  I spray with Liquid Cop twice and it cleared up