Could it be citrus greening? Europe

[Marcin]

This problem has been posted recently on Polish citrus group on Facebook. The leaves on this tree started to develop irregular yellowing pattern. The problem started about a month ago. The tree was purchased this spring, it was probably imported from southern Europe.

The question is - could it be citrus greening disease?

[1rainman]

Could be but unlikely. You'll know it's greening as the tree slowly dies. Looks more like a nutrient issue or related to salts in the soil or something.

[Vegan Potato Man]

Yes it looks like a micronutrient deficiency. Possibly linked to substrate PH.

[Millet]

HLB in Poland is unlikely.  However, the leaves do have the look of an HLB infection.

[Marcin]

Yes, I know HLB is unlikely in Poland but because it's a market-bought plant, probably imported, then maybe its not impossible. Thank you for the answers.

[poncirsguy]

You are correct on possibilities but if it isn't HLB  you re in luck.

[Citradia]

Even if you have an infected tree, you won’t have psillids in Poland to spread it.

[Marcin]

Thanks for the replies. That's true - even if this tree is infected, there are no psyllids in Poland which would fly on distance and infect other plants. If other citrus plants are isolated from that one, they should be safe.

[Ilya11]

From what I know the patogenic bacteria has not been yet introduced in Mediterranean.
Only small numbers African psyllid vector T.erytryae  has been found in Portugal and in few hectares of citrus in Israel Asian psyllid D.citri was reported this year.

[1rainman]

Looking at it again it could be root bound in a small pot and need a good fertilizing with micro nutrients. Citrus like bone meal due to high calcium

[Marcin]

Thank you, Ilya for the information. It's good to know that there have been no reports of the disease in Europe.
1rainman, thanks for the suggestions.

[tedburn]

Hope, that our winter in middle Europe are still cold enough to kill these pests 

[lebmung]

I could say it's a zinc and magnesium deficiency. Perhaps you overapplied potassium for Mg
Applying phosphorus at a high rate prevents  uptake of zinc, copper, iron and manganese

[tedburn]

https://www.freshfruitportal.com/news/2022/11/01/african-hlb-vector-spreads-along-the-coast-of-portugal-threatens-huelva-citrus-fruits/

Just found this article