If symptoms appear on new leaves, the problems could related to iron, zinc, manganese, copper, boron, calcium, or sulfur.
Deficiency: discoloring of the leaves mainly between the veins, starting with the lower/middle leaves. when i say discoloring, i dont mean a light green, i mean almost white. its a bleaching that starts at the top, and moves down, eventually, necrotic spots appear. this can be caused by over watering, excessive salts,
Leaves on growing shoots turn pale and veins remain dark green. pH
imbalances make iron insoluble. Foliar feed with chemical fertilizer
containing Fe or rusty water.