What is the difference between erythema (leaf mold) and leaf spot? Thank you for your

Leaf spot was originally a small round brown type, which expanded into a round or semi-circular lesion with brown or grayish brown in the middle, and a dark green mold layer could be produced on both sides of the leaf. Erythema is a little red at first, and it is irregular dark red spots after expansion. When the humidity on the back of the leaves is high, a dark green velvet layer will be produced, and the stem will become ill, resulting in purple-brown long concave spots and no mildew layer.