Planets seem basically healthy. However, the uppermost leaves are getting clusters of very small black spots on the leaves. It doesn't look like leaves are being eaten for the most part. Spots go thru the leaves, visible from top and bottom. Not sure if it is insect, fungal, or bacterial. Lower leaves do not seem to be affected. Basil is planet in a pot along with parsley, which is unaffected. Can you identify, and suggest treatment?