On Sunday afternoon while picking some spinach for salad, I found some small, what looked like, black bugs on the underside of some of the spinach leaves in my greenhouse. They seemed to be localized to one or two plants. I pulled the plants and disposed of them outside the greenhouse. Yesterday, I only found 1 leaf with a couple of those black "bugs". I picked it, and after looking at it through my 30x magnifying lens decided it is not a bug at all. I took a pin and easily opened it up. It was soft and black throughout. Not sure what it is. Any guesses?
Here's pic I found on the internet of it on a basil leaf.
Here's another one (ignore the powdery mildew in this picture)