Splotched Rollinia Seedling Leaves

[ktorg]

Hi all,

I have a rollinia seedling that is about a foot tall and growing quickly, but over the last few weeks its leaves have become blotchy with black and yellow spots as seen in the attached pictures. After the discoloration gets to a certain point then they start falling off.

Anyone know what is going on here and how I can fix it?

Thanks!

[Guanabanus]

Not enough Potassium.