The first two pictures, I'm not sure what it is but I would guess perhaps some damage caused by some insect. Not sure what to do about it.
The last picture looks like a pretty heavy aphid infestation along with some scale insects (the little white things) and I see an ant so you might be dealing with aphids being farmed by ants as well.
I would remove the most heavily infested leaves or whole plants if it is that bad and then probably spray with seaweed extract or worm tea to see if it helps against the problem on other plants. Often the pests will attack plants that are struggling anyway so see if you can figure a pattern as to what plants are thriving and pest free and which plants are struggling. (light, aeration, shade, air movement etc.)
Ants definately are natures smart farmers. In 10 years I've had peaches on my farm, I never had to spray them once. Every spring the blossoms are loaded with ants working over every blossom. 2 years ago my tree split in half from the weight of the peaches ( I waited too long before plucking off the bad). Anyways when I have lots of ants, I have lots of peaches, they never ever bother the peaches on the tree and drive off other flying insects, they only harvest the peaches if and when any hit the ground, then when they hit the ground they have streams of them hauling away the fruit to their dens for storage. Their den is in the root of the trees at the base.
This year, I got hit by army worms that decimated my peaches, had to spray just to make sure they didn't reach adulthood and multiply and hit me again next year, they bore into the peaches internally all the way to the seeds and ruin them.
The ants might not be doing the damage directly but just watch them closely for aphids, or think about planting something ants like instead. Ants for the most part nurture plants...unles they are those dang corporate farming ants who try to maximize everything with their aphid slave labor LOL.