Looks to be fungal; but I doubt CBS. Spray it with a good fungicide and it should disappear. Alternatively, for a small tree, cleaning with alcohol mixed with water and applied with a Q-tip should solve your problem. Sometimes you get black mold as a result of a scale infestation; the black mold feeds on the sticky exudate of the scales.

Thanks John. Just spoke to the head of citrus pathology and based on that pic I texted he also said it was black mold, (a saprophytic fungus he said). Sounds like copper fungicide should do the trick. There is yellow stuff on the leaves which I assume is just that but unfortunately there doesn't seem to be any on the infected leaves. So I'll just respray and continue to isolate a bit and take it from there.

Thanks for your expert opinion.

I took the leaves to the ag extension office and the person who does the inspection won't be in until after Thanksgiving. I left the leaves with the receptionist and will report the findings when I get the results back.

petunia fish, did the gentleman you spoke to recommend a specific product by name? There are many products on the market and I was just wondering if one was better than another for the job. I was looking at a fungicide at Lowes yesterday and was not sure which one to purchase. Does Bonide sound familiar? I think that is what I looked at but did not purchase because I did not know what I was dealing with.

I took all the leaves off that I could find with the black spots and am keeping it isolated from my other trees as well.

johnmerr The black mold we are dealing with is not sooty mold. I have dealt with that in the past. This is something different. Sooty mold looks different in that it is a thin layer while this looks more like a paintball splat an fuzzy looking. You have to see both together to understand the difference. My explanation is probably not very good. Sorry.

Before I contacted Fl Dept of Ag, I emailed UC Riverside Ag dept about this and someone nicely replied. For peace of mind only I sent a pic of a leaf on her request. The one thing that bothered me about the Fl pathologist is that he said CBS doesn't affect leaves, but I can see online that it does. Will report anything they say.

Denise, don't know if it matters what kind of copper fungicide you would use. But what do I know? lol. I use Monterey which lists copper at 6%. It handled a couple of plumeria with a fungus about a year ago. Have the sense that we are doing all the right things unless UCR says something different.

Btw, this tree is stunningly gorgeous standing a few feet away.

My Moro has many leaves (about 70%) with yellow tips with brown sports. The spots are located only on those yellow tips.

Is it a disease?

this looks like fertilizer burn to me.

I hope it is nothing serious.

Or salt buildup from irrigation water.

Mikhail what kind of water do you use for watering your citrus? Does it go through water softener?

Only regular municipal (tap) water.

Can it be too much water? We had some rainy days recently and soil is still very wet.

No, rainwater would not cause this. I don't know the quality of your tap water. If you have a lot of rain, can you collect it in barrel and use this for watering your tree?

I checked my tree again and found some of the black spots. First let me say this. USDA came a couple of times and inspected Harris facility. I would think they would have spotted something incurable? Also every tree gets inspected by Harris before it is going out. I have no doubt that the trees will be just fine.

and here is the new growth. I also would like to mention that I have warm and humid conditions in my grow room. Does not look like the spots are spreading?

Susanne. That's exactly what the black spots on my Shiranui looked like. Very relieved, and the new growth is spectacular.

Mine's a heck of a beautiful tree. I'll be ordering again soon. This is about the prettiest and most lush citrus I've ever owned. A lot of tree for the price!

Thanks for your input.

Susanna, our tap water is supposed to be very good. So they say at least.

We had some heavy rain several days ago but it is not a typical thing here (except for last year :). I think we experience around 20 inches of annual rainfall and less where I live. My particular area is protected from ocean winds/cyclones by El Monte Diablo. So I have to rely pretty much only on tap water.

If it is not the water then maybe too much fertilizer? What do you use for feeding your tree?

Citrus tone (in July and late September) + Bush Doctor Microbe Brew (weekly) + Fish 5-1-1 (2-3 times per month). Maybe it was too much for a small tree.