This is the fourth year I've been growing tomatoes in my garden, but this is the first time I see this pest affecting my plants. The plants have black, brown spots on yellowing leaves. On some of the plants (see first two photos), the pest has affected also the stem and/or branches.
I'm growing a mix of stored-bought and grown-from-seeds plants. The plants have been outside for more than a month now, and receive daily watering. They are growing in pots. We've had a month of fairly warm, dry weather (25-30 Celsius, or around 80 F).
Any help is much appreciated!