A disease of blackcurrant bushes in which the buds become swollen due to the presence of gall mites.
The mite is Cecidophyopsis ribis, family Eriophyidae
 Example sentencesExamples
-  During the winter I renovated an old row of redcurrants, quite successfully it seems, but now I realise that I have inadvertently retained a blackcurrant bush that has big bud reversion.
 -  Look to blackcurrants for ‘big bud’; pinch off infected buds and burn them.
 -  It is spread by a mite vector, the blackcurrant gall mite, or big bud mite, Cecidophyopsis ribis.
 -  We've been asked not to have bonfires on the allotment, and fair enough but what to do with a big blackcurrant bush uprooted due to big bud
 -  Always watch out for Big Bud in the Spring and pick off the bigger buds before the trouble gets a real hold.