Small flower chrysanthemum Bad disease.

[Nemesia]

I have done a lot of cuttings of this easily grown chrysanthemum. It has brilliant white smallish flowers. But, the mother plant has got some kind of disease. Every leaf has brown blotches.  Will it still flower? What is the disease? If I cut off all the stems will it survive? Thank you.

[Nemesia]

[Tyke]

Not sure what it is, but i have had 2 lots of garden centre bought chrysanthemums die on me after a few weeks - nice flowers that it all goes brown and dies.

[Nemesia]

This plant has done well for two years previously so the problem is something that has occurred this year.  The cuttings I have done are all fine.  I'll look up chrysanths with Google and try and find out what it is.