Why is there black dots on the leaves of my wave petunias?

Question

Why is there black dots on the leaves of my wave petunias?

Answer 1

This is Melon Cotton aphid, small black or dark green aphids. Sooty mould grows on the aphids excrement on flowers and undersides of leaves, which look like black spots. Spray as directed with an insecticide.

Answer 2

I dont know