Unsure what is harming my potato plants
I planted some potato plants in grow bags two months ago. I bought potatoes with tubers from a garden centre, and that is what I planted. I planted them in compost bought from the garden centre.
They were growing well, and after about 6 weeks I noticed holes in the leaves, perhaps caused by something eating them. So then I bough pesticide from the garden centre, which said it was fine for potato plants and sprayed them. After 8 weeks a lot of the plants have wilted and are bending over, as if they are too weak to stand. Some have dried out completely their leaves and some have grey spots on their leaves. Does anyone have advice on what the problem(s) might be?
I attach assorted pictures showing the symptoms.