Blackcurrant problem - Big Bud?

Hi

I have a number of blackcurrant bushes which I think have got Big Bud? 

I can't seem to find any mention of this on the www except as a form of cannabis plant with the same name (£8.75 for one seed - wow!).

Does anyone have an organic cure and does it affect the bush for the future?

Thanks for any help.
DD

Thanks for quick reply - hope the rain stops soon so I can get out and pick the buds off tomorrow.

It's going to be a big job - might end up digging them out too!!