Leaf Cupping & Magnesium Question

[Piss P]

Howdy All,

I have two questions for the group with pictures attached. Any and all comments are welcomed!

1) I have a potted yuzu that has severe cupping of its latest foliage. The leaves/plant seems very healthy otherwise and is about to start a new flush. Has anyone else dealt with this? I could not find much info on this specific downward cupping of citrus leaves elsewhere - the little I did find had people hypothesizing under watering being the issue. However I do not think that is an issue for my plant.


2) My potted NZL started showing signs of what I thought to be Mg deficiency and I threw a large pinch of MgSO4 at the base of the plant and have watered as usual for 7 days now. How quickly should I be noticing a difference in the foliage if it is indeed a Mg problem? As of yet there hasn't been noticeable change. Looking at the diagnosis resources online, boron toxicity matches the appearance of the problem but that seems quite niche for a recently potted plant (3.5 months). The plant is in a flush and otherwise seems to be putting out growth at a steady pace - to note, new leaves at top of plant are showing signs of the same chlorosis but new leaves on lower branch do not show any signs of problem.

Again, any opinions are greatly welcomed!

Thanks,
pp

[matt_citrus]

The downward cupping can sometimes mean overwatering (or vapor pressures inconsistent with plant moisture). Plant is trying to shed moisture.

[Millet]

Looking at the leaves I'm not sure that it is even a magnesium deficiency.  However, depending on the severity of a magnesium deficient leave the leaves affected do not regain full recoloration.

[Piss P]

The downward cupping can sometimes mean overwatering (or vapor pressures inconsistent with plant moisture). Plant is trying to shed moisture.

Oh interesting - this might be at play. Do you know any papers or online resources on this topic? Really appreciate the feedback

[Piss P]

Looking at the leaves I'm not sure that it is even a magnesium deficiency.  However, depending on the severity of a magnesium deficient leave the leaves affected do not regain full recoloration.

Good to know! Care to wager a guess as to what may be ailing it then?

[tedburn]

Regarding first picture in this link, it resembles a Zinc deficiency
https://www.yara.fr/fertilisation/solutions-pour-cultures/agrumes/carences-agrumes/