Dark spots on dwarf lemon tree leaves

[gabbleduck]

Dwarf lemon and dwarf meyer lemon trees grown in containers, South East US. Both exhibit same symptoms.

I've had this recurring for a few years. It mostly affects older leaves and does not affect the fruit at all (yet?). 

One side of the leaf has yellowed sections with dark spots, the other side of the leaf has a very slight yellowing but no spots or dark areas.
Usually the top side is affected but there are a few leaves where the underside has the spots and top looks fine.
Dark spots are not raised and it would be hard to distinguish between affected and non affected leaves by touch.

Seems to be randomly distributed among branches, no obvious pattern or location e.g. all leaves on one branch, only lower leaves, only old leaves.

No obvious insects.

My best guess is greasy spot? but pictures online seem different and I have read that it starts on the underside of leaf.

Topside




Underside

[david]

Greasy spot is exactly that. A greasy spot that develops on leaves. It looks and feels just like a greasy spot. In your pics I do not see it. I think you have something else or perhaps normal leaf attrition. Can you show me a close up of the damage? Welcome to the forum. Lots of knowledgeable folks in here. They will chime in. If you would like to treat it as greasy spot.....do this. Greasy spot is a fungus disease. If you will spray the tree with a good copper fungicide that will take care of it. Copper can be purchased at Home Depot or any of the big box stores. Be safe and spray......can not hurt to spray.

[gabbleduck]

Thanks for that, if it is supposed to feel different then I would say it's definitely not greasy spot.

Natural attrition makes more sense based on how the plant is behaving I've just never seen it look like this (and new to citrus).

Here's the best I can do for a close up.

[kelley]

I’ve had leaves like this, post-CLM damage. In my uneducated opinion, it comes with the territory with CLM (leaf miner).

[darthstewie]

That is not a leaf minor! That looks like a vitamin/nutrient deficiency. Leaf minors look like they are boring roadways under and on top of your leaves. Another thing with leaf minors on one side of the roadway you will see what looks like a itty bitty worm inside that roadway. Everytime i think i have them undercontrol they show up. I wash the leaves i have bathethem in neem oil with soap, used 7 dust, reintroduced good living organics and still.

[kelley]

Agreed, Stewie - I’ve had leaves turn dark like this on top of old tunnels. No, the new damage doesn’t look like that. Apologies for the confusion.