It is difficult to imagine a dacha or a manor in Russia, Ukraine, Belarus without currant bushes. If they hit the plant, most likely it will have to be destroyed.
But there are pests that can be dealt with by less radical methods. For example, aphids on currants. Of course, you can use chemicals to remove it, but you want the berry not to contain harmful elements. I think so. Aphids on currants do not appear on their own. She is bred by ants as a cow (to get milk). Therefore, if aphids have started up on the currants, you need to look for an anthill nearby. It is usually found in the roots of the bush. First you need to get rid of the ants. To do this, in early spring, pour a bucket of boiling water under the bush. This will not harm the currant, and the ants will die.
Now all that remains is to clear the bush from the aphids wintering on it. It is located inside the kidneys, which are easily distinguished by their appearance. They are large and bead-like. We collect these kidneys and burn them. If it happens in the summer, then you can insist a kilogram of wood ash, insist it on a bucket of boiling water and spray the bush. Aphids usually die. You can also sprinkle the currants with red pepper tincture.