The affected areas appear pale rather than brown; has your plant recently made a transition to hot sun, burning the leaves, or is is out in the open year round?

hi larry_gene

Thanks for replying. The plant has been in full sone all the time and I am in Germany. Currently for many weeks now we are having quite cloudy time and once a while very sunny.

I add ammonium sulfate to my brambles and they are very sensitive to the slightest overage.
This pic looks just like mine and the next several days they seem to dry up and die.
Fertilizer can do this and it also looks like leaf hopper damage.
Just a thought.

I'm thinking this looks likes spider mite which is fairly common on Black Currants. In containers they may be a little stressed and therefore more susceptible.

Here is a link that might be useful: More than you ever wanted to know about Black Currants

Agree with the thought about spider mites.

Thanks guys for posting. If spider mites, I should be able to see the white mites. There aren't any mites (at least view from naked eyes).

I will add liquid fertilizer in the next watering.