Q.leaves on my rose bush turned black and fell off
I noticed eggs on a couple of my thornless pink roses. I mixed up a batch of dish soap and water. Instead of using dawn, as I have done for over 30 years, I used the Family Dollar brand. I sprayed that evening. By midday I noticed my leaves where actually turning a black. This is one week later and I have only maybe 10 leaves. My rose stands 6′ and 3′ around. It was gorgeous till I sprayed. Do I cut the rose back or just leave it be?

Perhaps the solution was too strong and you burnt the plant. That happened to me once when I was too enthusiastic in ridding my orchid of aphids/thrips. The plant may not die (my orchid is still alive years later). I suspect the damaged leaves will continue to fall off and new ones will eventually appear. Since healthy leaves feed a plant, you may prune the bush to encourage new growth and lessen stress on the plant.